Re: What is the meaning of $normalize->{$1}
Op donderdag 15 juni 2023 22:31:31 CEST schreef Claude Brown:
> Is there any prior mention of "$normalise" in the script?
Only now I see the first mentioning of $normalize as:
$normalize = {}
The naming of it is quite confusing to me. More logically would have been
"present".
Now I understand that it is a test to assure certain lines in the input file
should not be present more than once.
> Assuming there isn't, most likely "$normalise->{$1}" is building out a
> hash-table with "$1" as the key and a value of 1 at each entry.
> $normalise will be a reference to that hash.
>
> To check if this is correct, do this sometime after this code:
>
> use Data::Dumper;
> print Dumper($normalise);
Thanks a lot.
--
fr.gr.
Freek de Kruijf
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: What is the meaning of $normalize->{$1}
Freek de Kruijf writes:
> Hi,
>
> I am trying to understand fully a perl program with the following lines:
>
>} elsif( /^(\#?\s*(?:pickup|qmgr)\s+)(?:fifo|unix)(\s+.*)/ ) {
> if( defined $normalize->{$1} ) { next; } else { $normalize->{$1} = 1; }
> I do understand the first line, but I can not find what the second line is
> about.
$1 contains the content of the first capturing group in the matching
regexp. in this case, "#pickup", "#qmgr", "pickup", "qmgr"... etc.
$normalize->{$1} means: getting the corresponding value of $1 from the
HashRef $normalize.
$normalize->{$1} = 1 means: setting the corresponding value of $1 to 1.
`next` is a keyword for skipping the rest of loop, so it would seem to
me that these 2 lines is inside of a loop. I'm guessing $_ is the
iterator of the loop. Assuming that's the case, it appears to me
$normalize is used to keep track the occurance of the captured
words. Not how may times they occur, just if they occur or not.
--
Cheers,
Kang-min Liu
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: What is the meaning of $normalize->{$1}
} elsif( /^(\#?\s*(?:pickup|qmgr)\s+)(?:fifo|unix)(\s+.*)/ ) {
if( defined $normalize->{$1} ) { next; } else { $normalize->{$1} = 1;
}
if the string starting at the beginning of the line matches, $1 will
contain "zero or one #, zero or more whitespaces, either the word "pickup"
or "qmgr", one or more whitespace" - it's then being used as the kev value
in the hash referenced by $normalize - if that entry already has a true
value (probably a 1) don't do anything, otherwise, assign that key a 1 .
Note, to fully match, that string has to be followed by either "fifo" or
"unix" and 1 or more whitespaces. Everything (including those last
whitespaces) will end up $2.
I'm a tad puzzled as to what the purpose could be, there certainly are
easier ways to do this. The "use " is including the module
.pm in the code, so it's subs/methods etc can be used by the
program.
On Thu, Jun 15, 2023 at 2:29 PM Freek de Kruijf
wrote:
> Hi,
>
> I am trying to understand fully a perl program with the following lines:
>
>} elsif( /^(\#?\s*(?:pickup|qmgr)\s+)(?:fifo|unix)(\s+.*)/ ) {
> if( defined $normalize->{$1} ) { next; } else { $normalize->{$1} =
> 1; }
> I do understand the first line, but I can not find what the second line is
> about.
>
> As far as can see the tested line in $_, from a file, is all ASCII with
> lower
> case characters. At the begin of the perl program the is no "use
> ".
>
> --
>
> fr.gr.
>
> Freek de Kruijf
>
>
>
>
> --
> To unsubscribe, e-mail: beginners-unsubscr...@perl.org
> For additional commands, e-mail: beginners-h...@perl.org
> http://learn.perl.org/
>
>
>
--
a
Andy Bach,
afb...@gmail.com
608 658-1890 cell
608 261-5738 wk
What is the meaning of $normalize->{$1}
Hi,
I am trying to understand fully a perl program with the following lines:
} elsif( /^(\#?\s*(?:pickup|qmgr)\s+)(?:fifo|unix)(\s+.*)/ ) {
if( defined $normalize->{$1} ) { next; } else { $normalize->{$1} = 1; }
I do understand the first line, but I can not find what the second line is
about.
As far as can see the tested line in $_, from a file, is all ASCII with lower
case characters. At the begin of the perl program the is no "use ".
--
fr.gr.
Freek de Kruijf
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
What Happened to Net::DNS and a few others on December 1?
We run some FreeBSD systems using FreeBSD9.1 and 9.3 and the response to perl -version is: This is perl 5, version 18, subversion 4 (v5.18.4) built for amd64-freebsd-thread-multi On December 1 of 2014, we were alerted to the fact that some perl scripts were no longer working. The complaint was about Net::DNS on one system and Warnings::Unused on another system and expect.pm on yet another system. I used cpanp -i to install all the needed modules with no trouble at all and all the scripts came back to life. I am not complaining at all but curious as to what mechanism caused older modules to basically expire and need to be replaced. Thank you. Martin McCormick -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: What Happened to Net::DNS and a few others on December 1?
Hi Martin, On Tue, 02 Dec 2014 11:45:58 -0600 Martin G. McCormick mar...@server1.shellworld.net wrote: We run some FreeBSD systems using FreeBSD9.1 and 9.3 and the response to perl -version is: This is perl 5, version 18, subversion 4 (v5.18.4) built for amd64-freebsd-thread-multi On December 1 of 2014, we were alerted to the fact that some perl scripts were no longer working. The complaint was about Net::DNS on one system and Warnings::Unused on another system and expect.pm on yet another system. I used cpanp -i to install all the needed modules with no trouble at all and all the scripts came back to life. I am not complaining at all but curious as to what mechanism caused older modules to basically expire and need to be replaced. There could be several reasons: 1. The @INC of the installed module was perl-version-specific. E.g in my perl -V: /usr/lib/perl5/site_perl/5.20.1 /usr/lib/perl5/site_perl/5.20.1/x86_64-linux-thread-multi /usr/lib/perl5/site_perl/5.20.0 /usr/lib/perl5/site_perl/5.20.0/x86_64-linux-thread-multi /usr/lib/perl5/site_perl/5.18.2 /usr/lib/perl5/site_perl/5.18.1 /usr/lib/perl5/site_perl/5.18.0 /usr/lib/perl5/site_perl/5.16.3 /usr/lib/perl5/site_perl/5.16.3 /usr/lib/perl5/site_perl/5.16.2 /usr/lib/perl5/site_perl/5.16.2 /usr/lib/perl5/site_perl/5.16.1 /usr/lib/perl5/site_perl/5.16.1 /usr/lib/perl5/site_perl /usr/lib/perl5/vendor_perl/5.20.1 /usr/lib/perl5/vendor_perl/5.20.1/x86_64-linux-thread-multi /usr/lib/perl5/vendor_perl/5.20.0 /usr/lib/perl5/vendor_perl/5.20.0/x86_64-linux-thread-multi /usr/lib/perl5/vendor_perl/5.18.2 /usr/lib/perl5/vendor_perl/5.18.1 /usr/lib/perl5/vendor_perl/5.18.0 /usr/lib/perl5/vendor_perl/5.16.3 /usr/lib/perl5/vendor_perl/5.16.3 /usr/lib/perl5/vendor_perl/5.16.2 /usr/lib/perl5/vendor_perl/5.16.2 /usr/lib/perl5/vendor_perl/5.16.1 /usr/lib/perl5/vendor_perl/5.16.1 /usr/lib/perl5/vendor_perl/5.16.0 /usr/lib/perl5/vendor_perl/5.16.0 As you can see, some of them are versioned and if the previous versions are not added to the inc of the new perl, the modules installed there won't be available. 2. Sometimes new versions of perl-5.x break the XS API or ABI and can no longer load the shared libraries that are associated with some binary-including modules. 3. Possible other reasons. Regards, Shlomi Fish Thank you. Martin McCormick -- - Shlomi Fish http://www.shlomifish.org/ Stop Using MSIE - http://www.shlomifish.org/no-ie/ God gave us two eyes and ten fingers so we will type five times as much as we read. Please reply to list if it's a mailing list post - http://shlom.in/reply . -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: What Happened to Net::DNS and a few others on December 1?
Shlomi Fish writes: There could be several reasons: 1. The @INC of the installed module was perl-version-specific. E.g in my perl -V: As you can see, some of them are versioned and if the previous versions are not added to the inc of the new perl, the modules installed there won't be available. 2. Sometimes new versions of perl-5.x break the XS API or ABI and can no longer load the shared libraries that are associated with some binary-including modules. 3. Possible other reasons. Thanks very much. I suspect your second reason was what happened here. Martin -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
perlre(1) and substitution evaluations
perlre(1) seems to be missing information about substitution evaluations with the /e option. The functionality is present in perl: perl -e '$_=2; s/2/1+3/e; print' But it is not listed in the pod documentation for v5.16.3 or v5.18.1. The modifier /e is described in Programming Perl, 4th ed, pp 186, 254-255. Where should suggestions for corrections be sent? Could something like the text below be added? Regards, /Lars $ diff perlre.pod perlre.pod.orig 108,113d107 =item e X/e Treat the replacement portion as an interpreted expression. Each additional C/e modifier after the first functions as an eval() around the code to execute. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: perlre(1) and substitution evaluations
Lars Noodén lars.noo...@gmail.com wrote: perlre(1) seems to be missing information about substitution evaluations with the /e option. The functionality is present in perl: perl -e '$_=2; s/2/1+3/e; print' But it is not listed in the pod documentation for v5.16.3 or v5.18.1. The modifier /e is described in Programming Perl, 4th ed, pp 186, 254-255. Where should suggestions for corrections be sent? Could something like the text below be added? Regards, /Lars $ diff perlre.pod perlre.pod.orig 108,113d107 =item e X/e Treat the replacement portion as an interpreted expression. Each additional C/e modifier after the first functions as an eval() around the code to execute. The substituted string isn't a regular expression. The substitute operator s/// is described in `perlop`. Rob -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: perlre(1) and substitution evaluations
On 11/30/2013 4:07 AM, Lars Noodén wrote: perlre(1) seems to be missing information about substitution evaluations with the /e option. The functionality is present in perl: perl -e '$_=2; s/2/1+3/e; print' But it is not listed in the pod documentation for v5.16.3 or v5.18.1. The modifier /e is described in Programming Perl, 4th ed, pp 186, 254-255. Where should suggestions for corrections be sent? Could something like the text below be added? Regards, /Lars $ diff perlre.pod perlre.pod.orig 108,113d107 =item e X/e Treat the replacement portion as an interpreted expression. Each additional C/e modifier after the first functions as an eval() around the code to execute. See the substitution operator in perlop: |||http://perldoc.perl.org/functions/s.html| A |/e| will cause the replacement portion to be treated as a full-fledged Perl expression and evaluated right then and there. It is, however, syntax checked at compile-time. A second |e| modifier will cause the replacement portion to be |eval http://perldoc.perl.org/functions/eval.html|ed before being run as a Perl expression. ... Here's the cross ref. in perlre: For reference on how regular expressions are used in matchings of m//, operations, plus various examples of the same, see discussions of m//, s///, qr// and ?? in Regexp Quote-Like Operators in perlop.ls of Modifiers quoted constructs in perlop -- Charles DeRykus -- Charles DeRykus
Re: perlre(1) and substitution evaluations
On 11/30/2013 02:55 PM, Charles DeRykus wrote: See the substitution operator in perlop: |||http://perldoc.perl.org/functions/s.html| A |/e| will cause the replacement portion to be treated as a full-fledged Perl expression and evaluated right then and there. It is, however, syntax checked at compile-time. A second |e| modifier will cause the replacement portion to be |eval http://perldoc.perl.org/functions/eval.html|ed before being run as a Perl expression. ... Here's the cross ref. in perlre: For reference on how regular expressions are used in matchings of m//, operations, plus various examples of the same, see discussions of m//, s///, qr// and ?? in Regexp Quote-Like Operators in perlop.ls of Modifiers quoted constructs in perlop Thanks. I see those in perlop and perlfunc. In perlfunc, it is grouped as Regular expressions and pattern matching though that man page just points to perlop. A really clear description in perlre would help, since the other modifiers are already there and they belong all together. The two s/// modifiers, /e and /r, should be at least named in that group at least as one-line summaries. Regards, /Lars -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: perlre(1) and substitution evaluations
On 11/30/2013 5:16 AM, Lars Noodén wrote: On 11/30/2013 02:55 PM, Charles DeRykus wrote: [ .. Thanks. I see those in perlop and perlfunc. In perlfunc, it is grouped as Regular expressions and pattern matching though that man page just points to perlop. A really clear description in perlre would help, since the other modifiers are already there and they belong all together. The two s/// modifiers, /e and /r, should be at least named in that group at least as one-line summaries. Yes. IMO it should be much easier to find the doc ref's for /e and even /r too. I seem to recall strong advocacy in the past for adding this or similar pointers. Long overdue :) -- Charles DeRykus -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Intermediate Perl - Chapter 7 Exercise 1 Question
I am working my way through Intermediate Perl and have a question
concerning one of the exercises (It's a long-ish exercise, so I won't
bother typing it out as it's irrelevant to the question at hand). The
author's solution contains the following code:
... code ...
my ($gather, $yield) = gather_mtime_between($start, $stop);
find($gather, @starting_directories);
my @files = yield-();
... more code ...
sub gather_mtime_between{
my ($begin, $end) = @_;
my @files;
my $gatherer = sub {
*my $timestamp (stat $_)[9]*
unless (defined $timestamp) {
warn ...;
return;
}
...
};
...
}
My question is about the bold: Where is $_ getting its value?
Richard Johnson
Re: Intermediate Perl - Chapter 7 Exercise 1 Question
On 12/10/2012 04:39 PM, Rich Johnson wrote:
I am working my way through Intermediate Perl and have a question
concerning one of the exercises (It's a long-ish exercise, so I won't
bother typing it out as it's irrelevant to the question at hand). The
author's solution contains the following code:
... code ...
my ($gather, $yield) = gather_mtime_between($start, $stop);
find($gather, @starting_directories);
my @files = yield-();
... more code ...
sub gather_mtime_between{
my ($begin, $end) = @_;
my @files;
my $gatherer = sub {
*my $timestamp (stat $_)[9]*
unless (defined $timestamp) {
warn ...;
return;
}
...
};
...
}
My question is about the bold: Where is $_ getting its value?
first off, did you type that code in by hand? there is no = in the line
you marked with **.
you need to read the docs on the File::Find module. it does a callback
to a sub (in this case the code ref assigned to $gather from
gather_mtime_between). before it does each callback find() sets $_ to
the file it just found. there are other things set globally by find
which can be very useful so learn more about that module.
uri
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
My Long Script (1)
#!/usr/local/bin/perl
# use warnings;
# use strict;
# use diagnostics;
use CGI;
my $cgi = new CGI;
my (
$topic, $score, $lastnum, $answer, $anum,
$bnum, $cnum, $dnum, $enum,$smarts,
$playlevel, $c_topic, $c_smarts, $c_playlevel, $c_score,
$c_lastnum, $c_goodans, $stimulus, $texta, $textb,
$textc, $textd, $texte,$defnum, $smiley,
$feedback, $goodans, $restart, @data,@cat,
@term, @def, @story,@candidate, @termnum,
$sound
);
my $instructions = (Click the button next to the best response);
my $ops = 0;
# GET COOKIES
$topic = $cgi-cookie('topic');
$smarts= $cgi-cookie('smarts');
$playlevel = $cgi-cookie('playlevel');
$score = $cgi-cookie('score');
$lastnum = $cgi-cookie('lastnum');
$goodans = $cgi-cookie('goodans');
# IF NEW CATEGORY THEN (RE)START TUTORIAL, ELSE GET USER ANSWER
if ( $cgi-param('Category') ) {
$restart = 1;
$topic = $cgi-param('Category');
$smarts= 0;
$playlevel = 0;
$score = 0;
$lastnum = 0;
}
elsif ( $cgi-param('Answer') ) { $answer = $cgi-param('Answer'); }
elsif ( $cgi-param('Next') ) { $restart = 1; }
if ($topic) {# RUN TUTORIAL
if ( $answer and ( $playlevel 3 ) ) {
# SUBSTITUTE SPACE FOR '+' IN $answer
$_ = $answer;
s/\+/ /g;
$answer = $_;
# RTRIM $answer AND MAKE SURE IT'S ALL LOWER CASE
$answer =~ s/\s+$//;
$answer = lc($answer);
# FIX FRENCH CHARACTERS
if( $answer eq deja entendu ) { $answer = déjà entendu; }
elsif ( $answer eq deja vu ) { $answer = déjà vu; }
elsif ( $answer eq deja vecu ){ $answer = déjà vécu; }
elsif ( $answer eq folie a deux ) { $answer = folie à deux; }
elsif ( $answer eq jamais vecu ) { $answer = jamais vécu; }
elsif ( $answer eq d%e9j%e0 entendu ) { $answer = déjà entendu; }
elsif ( $answer eq d%e9j%e0 vu ) { $answer = déjà vu; }
elsif ( $answer eq d%e9j%e0 v%e9cu ) { $answer = déjà vécu; }
elsif ( $answer eq folie %e0 deux ) { $answer = folie à deux; }
elsif ( $answer eq jamais v%e9cu ){ $answer = jamais vécu; }
}# END PLAYLEVEL 4
# LOAD DATA
open FH, /home1/theinfp0/public_html/psychdef/tutorial.fil or die $!;
while (FH) {
if ( $topic eq REVIEW ) { $termnum[ $ops++ ] = $_; }
elsif (/$topic/) { $termnum[ $ops++ ] = $_; }
}
close FH;
$defnum = $ops;# NUMBER OF TERMS IN DATA SET
# PARSE $_ TO GET $term(32) $cat(16) $def(64) $story(128) via @data:
$ops = 0;
foreach (@termnum) {
@data = /(.{16})/g;
$cat[$ops] = $data[0];
$term[$ops] = $data[1] . $data[2];
$def[$ops] = $data[3] . $data[4] . $data[5] . $data[6];
$story[$ops] =
$data[7]
. $data[8]
. $data[9]
. $data[10]
. $data[11]
. $data[12]
. $data[13]
. $data[14];
# RIGHT TRIM STRINGS
$cat[$ops] =~ s/\s+$//;
$term[$ops] =~ s/\s+$//;
$def[$ops] =~ s/\s+$//;
$story[ $ops++ ] =~ s/\s+$//;
}
# EVALUATE RESPONSE AND PROVIDE FEEDBACK, ADJUSTING SCORES
if ( $answer and ( $answer ne $goodans ) ) { $answer = 0; }
if ($answer) {
$smarts++;
$score= ++$score + $playlevel;
$smiley = 1; # SUCCESS
$feedback = You got it right!;
}
else {
$smarts-- unless $restart;
$feedback = Better study this!;
}
if( $smarts -4 ) { $playlevel--; $smarts = 0; }
elsif ( $smarts 4 ) { $playlevel++; $smarts = 0; }
# NEXT QUESTION
if ( $answer or $restart ) {# AVOID CHANGING $lastnum FOR WRONG ANSWER
if ( $playlevel 1 ) {
while (1) {
$termnum[0] = int( rand($defnum) );
last unless ( $termnum[0] == $lastnum );
}
$lastnum = $termnum[0];
$stimulus = $term[ $termnum[0] ];
$candidate[0] = $def[ $termnum[0] ];
while (1) {
$termnum[1] = int( rand($defnum) );
last unless ( $termnum[1] == $termnum[0] );
}
$candidate[1] = $def[ $termnum[1] ];
$anum = int( rand(2) );
$bnum = abs( $anum - 1 );
$texta= $candidate[$anum];
$textb= $candidate[$bnum];
if ( $texta eq $candidate[0] ) { $goodans = A; }
else { $goodans = B; }
}
elsif ( $playlevel == 1 ) {
while (1) {
$termnum[0] = int( rand($defnum) );
last unless ( $termnum[0] == $lastnum );
}
$lastnum = $termnum[0
strict subs in use at -e line 1.
$ perl -Mstrict -wle '{my $char = chr(Ox394) ; print $char;}'
Bareword Ox394 not allowed while strict subs in use at -e line 1.
Execution of -e aborted due to compilation errors.
I don't understand the above error message well,
Thanks ahead for any explainations,
Best Regards,
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: strict subs in use at -e line 1.
On Tue, Mar 06, 2012 at 11:31:59PM +0800, lina wrote:
$ perl -Mstrict -wle '{my $char = chr(Ox394) ; print $char;}'
Bareword Ox394 not allowed while strict subs in use at -e line 1.
Execution of -e aborted due to compilation errors.
I don't understand the above error message well,
The immediate problem you are seeing is that you should be using the
number zero (0) rather than the uppercase letter O (O).
If you are not using a font which allows you to easily distinguish
between then two, may I suggest inconsolata as a good choice for
programming?
--
Paul Johnson - p...@pjcj.net
http://www.pjcj.net
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: strict subs in use at -e line 1.
On 12-03-06 10:31 AM, lina wrote:
$ perl -Mstrict -wle '{my $char = chr(Ox394) ; print $char;}'
Bareword Ox394 not allowed while strict subs in use at -e line 1.
Execution of -e aborted due to compilation errors.
I don't understand the above error message well,
Thanks ahead for any explainations,
Best Regards,
First time I tried it, I got the same error. But after goofing around a
bit, it started to work.
$ perl -Mstrict -wle '{my $char = chr(Ox394) ; print $char;}'
Bareword Ox394 not allowed while strict subs in use at -e line 1.
Execution of -e aborted due to compilation errors.
$ perl -Mstrict -wle '{my $char = chr(Ox94) ; print $char;}'
Bareword Ox94 not allowed while strict subs in use at -e line 1.
Execution of -e aborted due to compilation errors.
$ perl -Mstrict -wle '{my $char = chr(Ox4) ; print $char;}'
Bareword Ox4 not allowed while strict subs in use at -e line 1.
Execution of -e aborted due to compilation errors.
$ perl -Mstrict -wle '{my $char = chr(394) ; print $char;}'
Wide character in print at -e line 1.
Ɗ
$ perl -Mstrict -wle '{my $char = chr(0394) ; print $char;}'
Illegal octal digit '9' at -e line 1, at end of line
Execution of -e aborted due to compilation errors.
$ perl -Mstrict -wle '{my $char = chr(034) ; print $char;}'
$ perl -Mstrict -wle '{my $char = chr(044) ; print $char;}'
$
$ perl -e'print 0x34'
52$ perl -e'print chr(0x34)'
4$ perl -e'$char=chr(0x34)'
$ perl -e'$char=chr(0x34);print $char'
4$ perl -e'my$char=chr(0x34);print $char'
4$ perl Mstrict -wle '{my $char = chr(0x30) ; print $char;}'
0
$ perl -Mstrict -wle '{my $char = chr(0x394) ; print $char;}'
Wide character in print at -e line 1.
Δ
$
--
Just my 0.0002 million dollars worth,
Shawn
Programming is as much about organization and communication
as it is about coding.
It's Mutual Aid, not fierce competition, that's the dominate
force of evolution. Of course, anyone who has worked in
open source already knows this.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: strict subs in use at -e line 1.
On Tue, Mar 6, 2012 at 9:31 AM, lina lina.lastn...@gmail.com wrote:
$ perl -Mstrict -wle '{my $char = chr(Ox394) ; print $char;}'
Bareword Ox394 not allowed while strict subs in use at -e line 1.
Execution of -e aborted due to compilation errors.
I don't understand the above error message well,
Thanks ahead for any explainations,
Best Regards,
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
If you are simply trying to assign chr(0x394) to varible $char and
then print $char then the below will work.
perl -Mstrict -wle '{my $char = chr(0x394) ; print $char;}'
HTH,
Chris
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: strict subs in use at -e line 1.
On Tue, Mar 6, 2012 at 11:42 PM, Paul Johnson p...@pjcj.net wrote:
On Tue, Mar 06, 2012 at 11:31:59PM +0800, lina wrote:
$ perl -Mstrict -wle '{my $char = chr(Ox394) ; print $char;}'
Bareword Ox394 not allowed while strict subs in use at -e line 1.
Execution of -e aborted due to compilation errors.
I don't understand the above error message well,
The immediate problem you are seeing is that you should be using the
number zero (0) rather than the uppercase letter O (O).
Thanks, I have never tried the hexadecimal output before. I thought ...
why is 0, not O?
If you are not using a font which allows you to easily distinguish
between then two, may I suggest inconsolata as a good choice for
I can easily tell the two, I just read from pdf and took it as O,
just googled the inconsolata, I will stick to the gvim
Thanks again,
programming?
--
Paul Johnson - p...@pjcj.net
http://www.pjcj.net
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Can't use string (1) as a HASH ref while strict refs
Rob == Rob Dixon rob.di...@gmx.com writes: Rob Randal, as I opened, I had started to enjoy and respect your posts here Rob and elsewhere. You were never required to reply to my 'ignorant post', Rob yet you chose to show your foolish emptiness once again. But I am highly motivated to reduce and contain the damage caused by misinformation. You were spreading misinformation to others. If my reply to you had no impact on you, that is sad, but at least the others reading this thread will be more enlightened. -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.posterous.com/ for Smalltalk discussion -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Can't use string (1) as a HASH ref while strict refs
On 27/09/2011 17:35, Randal L. Schwartz wrote: Rob == Rob Dixonrob.di...@gmx.com writes: Rob Randal, as I opened, I had started to enjoy and respect your posts here Rob and elsewhere. You were never required to reply to my 'ignorant post', Rob yet you chose to show your foolish emptiness once again. But I am highly motivated to reduce and contain the damage caused by misinformation. You were spreading misinformation to others. If my reply to you had no impact on you, that is sad, but at least the others reading this thread will be more enlightened. If you think you are doing the community a favour by making it a threatening place place where people can expect their ideas to be met with sardonic derision then all I can do is ask you to think again. I doubt if I can say anything more to change your mind. Rob -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Can't use string (1) as a HASH ref while strict refs
On 21/09/2011 20:57, Randal L. Schwartz wrote:
Rob == Rob Dixonrob.di...@gmx.com writes:
Rob I don't have Try::Tiny installed, but will take a look.
I am back at my desk, and have this horror from you to respond to. I had
started to enjoy some of your posts, and hoped that your legendary
brutal negativity was beginning to lapse.
Whatever your thoughts, please drop the shield that says you are
responding to people's coding rather than the people themselves. The
difference is an age-old philosophy, and I would love to hear your
thoughts on the distinction.
I have an addressbar query shortcut of:
http://search.cpan.org/perldoc/#query#
aliased to perldoc, so I can type perldoc Try::Tiny and get the
latest manpage on it directly from the CPAN without installing it.
Hooray for you. I use my editor as an IDE to do the very same thing.
Rob If you mean that $@ may be accessed by several pieces of code
Rob when a program dies,
No. See the referenced docs.
I have thought a lot about how an 'eval' block may be unsafe, and have
commented several times to discourage it.
I have now read the POD for Try::Tiny, and I cannot see anything that I
hadn't already envisaged: that when a Perl process dies $@ may be
accessed by several pieces of code.
The Try::Tiny documentation says this
When you run an eval block and it succeeds, $@ will be cleared,
potentially clobbering an error that is currently being caught.
Oddly, you chose to misquote me by splitting a sentence. Your version of
my post is irregular and inappropriate. It is not what I would have written.
What I wrote was
I don't have Try::Tiny installed, but will take a look. If you mean that
$@ may be accessed by several pieces of code when a program dies, then I
agree, but my main concern is that try / catch are both simply
prototyped subroutines, and the compile can not tie things down to requiring
try BLOCK catch BLOCK;
Your version:
Rob then I agree, but my main concern is that try / catch are both
Rob simply prototyped subroutines, and the compile can not tie things
Rob down to requiring
Rob
Robtry BLOCK catch BLOCK;
Why does that matter? It's the semantics that you have to get right,
not just the syntax.
I am sure you know the answer to that. It matters because the
presentation of the mechanism is deceptive. It looks very like
while () {
:
}
continue
:
}
but instead is something very different. As I have described, it amounts
to two obscure prototyped subroutine definitions. From the source:
sub try (;@);
and
sub catch (;@);
which is far from what the average man expects of 'while', 'for',
'continue' and so on. It is a deception, and should not be published
until the equivalent functionality is part of the Perl language.
Rob Maybe Try::Tiny works differently but I can't see how it could
Rob cover this.
Again, read the referenced doc. It would have taken you about 5
minutes, and you wouldn't have had to write this entire ignorant reply
or waste my time replying to it.
Randal, as I opened, I had started to enjoy and respect your posts here
and elsewhere. You were never required to reply to my 'ignorant post',
yet you chose to show your foolish emptiness once again.
It seems to me that you place your entire worth in your extreme and
detailed knowledge of Perl and its teaching. Please believe me that, as
a fellow human being, I would love to hear about your personal
experiences and how programming has played a part in your character.
You certainly seem insecure, and your silliness about your criticism not
applying to a person but to their deeds needs to be washed ashore. Stop
it and be real. Believe me, you wouldn't cease to exist if you lost your
technical ability.
Rob
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Can't use string (1) as a HASH ref while strict refs
On 20/09/2011 15:57, Randal L. Schwartz wrote:
Rob == Rob Dixonrob.di...@gmx.com writes:
Rob For me, the bottom line is that try / catch is a funky showpiece that
Rob pushes Perl syntax beyond its limits. No one who sees your code will
Rob thank you for using it, and you should remove it in preference of a
Rob simple check on $@.
Completely disagree. Checking $@ *appears* to be easy, but is prone to
error. Try::Tiny is best of breed to fix this. I would prefer people
use Try::Tiny instead of trying to handcraft the $@ checking and getting
it wrong.
For example, if you don't know what's wrong with this:
eval { ... };
if ($@) { ... }
then you *need* to start using Try::Tiny.
See especially the section beginning BACKGROUND on the Try::Tiny
manpage.
I don't have Try::Tiny installed, but will take a look. If you mean that
$@ may be accessed by several pieces of code when a program dies, then I
agree, but my main concern is that try / catch are both simply
prototyped subroutines, and the compile can not tie things down to requiring
try BLOCK catch BLOCK;
Maybe Try::Tiny works differently but I can't see how it could cover this.
Rob
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Can't use string (1) as a HASH ref while strict refs
Rob == Rob Dixon rob.di...@gmx.com writes: Rob I don't have Try::Tiny installed, but will take a look. I have an addressbar query shortcut of: http://search.cpan.org/perldoc/#query# aliased to perldoc, so I can type perldoc Try::Tiny and get the latest manpage on it directly from the CPAN without installing it. Rob If you mean that Rob $@ may be accessed by several pieces of code when a program dies, No. See the referenced docs. Rob then I agree, but my main concern is that try / catch are both Rob simply prototyped subroutines, and the compile can not tie things Rob down to requiring Rob try BLOCK catch BLOCK; Why does that matter? It's the semantics that you have to get right, not just the syntax. Rob Maybe Try::Tiny works differently but I can't see how it could Rob cover this. Again, read the referenced doc. It would have taken you about 5 minutes, and you wouldn't have had to write this entire ignorant reply or waste my time replying to it. :( -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/ Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc. See http://methodsandmessages.posterous.com/ for Smalltalk discussion -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Can't use string (1) as a HASH ref while strict refs
Rob == Rob Dixon rob.di...@gmx.com writes:
Rob For me, the bottom line is that try / catch is a funky showpiece that
Rob pushes Perl syntax beyond its limits. No one who sees your code will
Rob thank you for using it, and you should remove it in preference of a
Rob simple check on $@.
Completely disagree. Checking $@ *appears* to be easy, but is prone to
error. Try::Tiny is best of breed to fix this. I would prefer people
use Try::Tiny instead of trying to handcraft the $@ checking and getting
it wrong.
For example, if you don't know what's wrong with this:
eval { ... };
if ($@) { ... }
then you *need* to start using Try::Tiny.
See especially the section beginning BACKGROUND on the Try::Tiny
manpage.
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
mer...@stonehenge.com URL:http://www.stonehenge.com/merlyn/
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
See http://methodsandmessages.posterous.com/ for Smalltalk discussion
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Can't use string (1) as a HASH ref while strict refs
Hi,
I was getting this error message for one of my script.
The reason came out out to be, I had not place a semi-colon at the end of
try-catch block.
try {
something
} catch some_exception {
do something
}
After I placed the semi-colon, I am no longer getting this error (Can't use
string (1) as a HASH ref while strict refs)
try {
something
} catch some_exception {
do something
};
My questions is I have quite a few scripts that are using the SAME try-catch
block without a semi-colon but those are working seamlessly. They why was I
getting the error for only this try-catch block.
Is there some rule which we need to follow while using try-catch in Perl?
Thanks,
Parag
Re: Can't use string (1) as a HASH ref while strict refs
On 9/19/11 Mon Sep 19, 2011 5:11 PM, Parag Kalra paragka...@gmail.com
scribbled:
Hi,
I was getting this error message for one of my script.
The reason came out out to be, I had not place a semi-colon at the end of
try-catch block.
try {
something
} catch some_exception {
do something
}
After I placed the semi-colon, I am no longer getting this error (Can't use
string (1) as a HASH ref while strict refs)
try {
something
} catch some_exception {
do something
};
My questions is I have quite a few scripts that are using the SAME try-catch
block without a semi-colon but those are working seamlessly. They why was I
getting the error for only this try-catch block.
Is there some rule which we need to follow while using try-catch in Perl?
Yes: always end your try-catch statement with a semicolon! :)
The try-catch mechanism is not part of the Perl language (not as of Perl
5.10, anyway). There are modules that provide try-catch via prototyped
functions try($) and catch() that take code blocks as their first
argument. These include Error.pm, TryCatch.pm, Try::Tiny.pm, Exception.pm,
and Fatal.pm (according to
http://en.wikipedia.org/wiki/Exception_handling_syntax#Perl).
Since these are functions and not language keywords, they require a
semicolon at the end so that the subsequent statements are not interpreted
as additional catch() {} blocks.
Are you using one of these modules?
The result of leaving off the semicolon probably depends upon what follows
after the last catch block. While most of your programs do not issue that
same error message, it is still likely that they are not doing what you want
them to do.
If you want further help, please post a complete, short program that
demonstrates your problem.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Can't use string (1) as a HASH ref while strict refs
On 20/09/2011 01:11, Parag Kalra wrote:
I was getting this error message for one of my script.
The reason came out out to be, I had not place a semi-colon at the end of
try-catch block.
try {
something
} catch some_exception {
do something
}
After I placed the semi-colon, I am no longer getting this error (Can't use
string (1) as a HASH ref while strict refs)
try {
something
} catch some_exception {
do something
};
My questions is I have quite a few scripts that are using the SAME try-catch
block without a semi-colon but those are working seamlessly. They why was I
getting the error for only this try-catch block.
Is there some rule which we need to follow while using try-catch in Perl?
Hi Parag
The first problem I see is that you are passing 'catch' the return value
of the subroutine 'some_exception' when it expects a code block. The
correct syntax is
try {
some code that may cause an exception
}
catch {
handle exception passed in $_
}
The way try / catch works is obscure, and presented in Programming Perl
as an example of how subroutine prototypes could be useful, but the
declaration of try looks like
sub try ($);
so to express its functionality your code should be formatted like this
try (
{ some code that may cause an exception },
catch ({
handle exception passed in $_
})
);
which clearly requires a semicolon after the closing parenthesis.
For me, the bottom line is that try / catch is a funky showpiece that
pushes Perl syntax beyond its limits. No one who sees your code will
thank you for using it, and you should remove it in preference of a
simple check on $@.
It cannot be a good sign if you don't understand where the semicolons
should go!
HTH,
Rob
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: File::path the option keep_root = 1 does not seem to work
On 19/04/2011 10:42, Agnello George wrote:
File::path the option keep_root = 1 does not seem to work for me
use File::Path;
rmtree( '/temp/auto', { verbose =1 , keep_root = 1});
it throw me the output
unlink /temp/auto/test6 unlink /temp/auto/test5 unlink /temp/auto/test4
rmdir /temp/auto
the option keep_root = 1 should keep the root path ??
You are right. I can't fault the code you have posted.
There must be something else wrong. Please show us the entire program?
Rob
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
File::path the option keep_root = 1 does not seem to work
hi
File::path the option keep_root = 1 does not seem to work for me
use File::Path;
rmtree( '/temp/auto', { verbose =1 , keep_root = 1});
it throw me the output
unlink /temp/auto/test6 unlink /temp/auto/test5 unlink /temp/auto/test4
rmdir /temp/auto
the option keep_root = 1 should keep the root path ??
--
Regards
Agnello D'souza
Re: Behavior of minimal when applied to - {1,}? ot to - {0,}?
Rob Dixon wrote in message news:4d48bdc7.6050...@gmx.com...
On 01/02/2011 02:30, Chris Charley wrote:
#!/usr/bin/perl
use strict;
use warnings;
$_ = [][12/21/10 18:39:22] [oasetup] [oasetup] [INFO] Installing the
HPOvXpl package...;
for my $re (qw{ ^\[(.+?)\] ^\[(.*?)\] }) {
my ($dt) = /$re/ or die Horrible death\n;;
print $re, ' ', '$dt', \n;
}
__END__
C:\Old_Data\perlpperl t5.pl
^\[(.+?)\] '][12/21/10 18:39:22'
^\[(.*?)\] ''
C:\Old_Data\perlp
My question in the code above is the '.+?' behavior. I had guessed
that it would attempt to match the empty brackets and fail, (because
it requires 1 or more characters). Instead, it captures the right
bracket and the left opening bracket and contents (date) of the
second bracket pair.
Does the regex first consume a character before checking the next
character to see if it is the first one *after* the expression the
'+?' is applied to. It seems to be the way this regex behaved.
Or does the regex see its going to fail with the empty first bracket
pair, and so tries to advance to somehow find a match? This seems
pretty vague.
I thought a regex first looks for the next character beyond the
expression the '+?' is applied to, before it consumes any characters?
That is the way the second regex, '.*?', behaved.
Hope it was clear enough. :-)
Hey Chris
/.+?/ requires at least one character, so /^\[.+?\]/ will need at least
three characters for a match. The engine will try to match /^\[.\]/ and
fail, then /^\[..\]/, then /^\[...\]/ and so on. Perl doesn't care that
the object string's second character is a ']' - all it has to do is
match /./ and that will do fine. This process continues until the
pattern is long enough to reach the first closing square bracket it
sees, and so comsumes the date/time field to get there.
/.*?/ will match zero characters, so the initial [] fits the bill
immediately. The ? doesn't change the lower bound of the character count
- it simply says to match as few as possible. /.{2,4}/ will match four
characters, while /.{2,4}?/ will match two.
HTH,
Rob
Hi Rob,
Thanks for the good answers from you and Uri. Yes, fulfilling the min of a
quantifier
before applying the lazy behavior of the ? is what had me stumped. The ?
doesn't change the lower bound and I was hazy in my mind about that.
Chris
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Behavior of minimal when applied to - {1,}? ot to - {0,}?
#!/usr/bin/perl
use strict;
use warnings;
$_ = [][12/21/10 18:39:22] [oasetup] [oasetup] [INFO] Installing the
HPOvXpl package...;
for my $re (qw{ ^\[(.+?)\] ^\[(.*?)\] }) {
my ($dt) = /$re/ or die Horrible death\n;;
print $re, ' ', '$dt', \n;
}
__END__
C:\Old_Data\perlpperl t5.pl
^\[(.+?)\] '][12/21/10 18:39:22'
^\[(.*?)\] ''
C:\Old_Data\perlp
My question in the code above is the '.+?' behavior. I had guessed that it
would
attempt to match the empty brackets and fail, (because it requires 1 or more
characters). Instead, it captures the right bracket and the left opening
bracket
and contents (date) of the second bracket pair.
Does the regex first consume a character before checking the next
character to see if it is the first one *after* the expression the '+?' is
applied to. It seems to be the way this regex behaved.
Or does the regex see its going to fail with the empty first bracket pair,
and so
tries to advance to somehow find a match? This seems pretty vague.
I thought a regex first looks for the next character beyond the
expression the '+?' is applied to, before it consumes any characters?
That is the way the second regex, '.*?', behaved.
Hope it was clear enough. :-)
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Behavior of minimal when applied to - {1,}? ot to - {0,}?
CC == Chris Charley char...@pulsenet.com writes:
CC #!/usr/bin/perl
CC use strict;
CC use warnings;
CC $_ = [][12/21/10 18:39:22] [oasetup] [oasetup] [INFO] Installing the
CC HPOvXpl package...;
CC for my $re (qw{ ^\[(.+?)\] ^\[(.*?)\] }) {
CCmy ($dt) = /$re/ or die Horrible death\n;;
CCprint $re, ' ', '$dt', \n;
CC }
CC __END__
CC C:\Old_Data\perlpperl t5.pl
CC ^\[(.+?)\] '][12/21/10 18:39:22'
CC ^\[(.*?)\] ''
CC C:\Old_Data\perlp
CC My question in the code above is the '.+?' behavior. I had guessed
CC that it would attempt to match the empty brackets and fail,
CC (because it requires 1 or more characters). Instead, it captures
CC the right bracket and the left opening bracket and contents (date)
CC of the second bracket pair.
the regex is working as you coded it.
CC Does the regex first consume a character before checking the next
CC character to see if it is the first one *after* the expression the '+?' is
CC applied to. It seems to be the way this regex behaved.
if a regex fails, it bumps the char pointer to the next data char and
starts over. but you have an anchor there so it must match at the
beginning. so it matches the leading [ as you ask. then it grabs until
it sees text followed by a ]. you got what you asked for.
CC Or does the regex see its going to fail with the empty first
CC bracket pair, and so tries to advance to somehow find a match?
CC This seems pretty vague.
nope. it is just what you said. the anchor forces it to grab the ] as it
satisfies the grab.
and without the anchor it still grabs the same thing since it does match
from the leading [ to a closing ] with text inside. the better way to
grab inside delimiters is to use a negated char class of the closing
delimiter. this grabs from a [ all the chars but a ] to the next ].
this works:
qr{\[([^]]+)\]}
i used qr's instead of qw's but it comes out the same.
uri
--
Uri Guttman -- u...@stemsystems.com http://www.sysarch.com --
- Perl Code Review , Architecture, Development, Training, Support --
- Gourmet Hot Cocoa Mix http://bestfriendscocoa.com -
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Behavior of minimal when applied to - {1,}? ot to - {0,}?
On 01/02/2011 02:30, Chris Charley wrote:
#!/usr/bin/perl
use strict;
use warnings;
$_ = [][12/21/10 18:39:22] [oasetup] [oasetup] [INFO] Installing the
HPOvXpl package...;
for my $re (qw{ ^\[(.+?)\] ^\[(.*?)\] }) {
my ($dt) = /$re/ or die Horrible death\n;;
print $re, ' ', '$dt', \n;
}
__END__
C:\Old_Data\perlpperl t5.pl
^\[(.+?)\] '][12/21/10 18:39:22'
^\[(.*?)\] ''
C:\Old_Data\perlp
My question in the code above is the '.+?' behavior. I had guessed
that it would attempt to match the empty brackets and fail, (because
it requires 1 or more characters). Instead, it captures the right
bracket and the left opening bracket and contents (date) of the
second bracket pair.
Does the regex first consume a character before checking the next
character to see if it is the first one *after* the expression the
'+?' is applied to. It seems to be the way this regex behaved.
Or does the regex see its going to fail with the empty first bracket
pair, and so tries to advance to somehow find a match? This seems
pretty vague.
I thought a regex first looks for the next character beyond the
expression the '+?' is applied to, before it consumes any characters?
That is the way the second regex, '.*?', behaved.
Hope it was clear enough. :-)
Hey Chris
/.+?/ requires at least one character, so /^\[.+?\]/ will need at least
three characters for a match. The engine will try to match /^\[.\]/ and
fail, then /^\[..\]/, then /^\[...\]/ and so on. Perl doesn't care that
the object string's second character is a ']' - all it has to do is
match /./ and that will do fine. This process continues until the
pattern is long enough to reach the first closing square bracket it
sees, and so comsumes the date/time field to get there.
/.*?/ will match zero characters, so the initial [] fits the bill
immediately. The ? doesn't change the lower bound of the character count
- it simply says to match as few as possible. /.{2,4}/ will match four
characters, while /.{2,4}?/ will match two.
HTH,
Rob
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Help with script How to prepend 2 lines instead of 1
Using the script below I need to add a second line with the following
text:
STAGEHDR|Barcoded
#!perl
use strict;
use warnings;
my $file = 'path/to/Access.csv';
my $newline = ENTHDR|1|3.0;
{
local @ARGV = ($file);
local $^I = '.bac';
while(){
if ($. == 1) {
print $newline$/;
}
else {
print;
}
}
}
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Help with script How to prepend 2 lines instead of 1
Hi Steve,
On Thursday 20 Jan 2011 21:10:39 steve1040 wrote:
Using the script below I need to add a second line with the following
text:
STAGEHDR|Barcoded
#!perl
use strict;
use warnings;
my $file = 'path/to/Access.csv';
my $newline = ENTHDR|1|3.0;
{
local @ARGV = ($file);
local $^I = '.bac';
while(){
Please avoid such games in any half-serious code. While they are useful from
the command line, they won't work properly within a larger code. See my
response to your earlier post with a proper way to do that and some other
pointers.
Regards,
Shlomi Fish
--
-
Shlomi Fish http://www.shlomifish.org/
Optimising Code for Speed - http://shlom.in/optimise
Chuck Norris can make the statement This statement is false a true one.
Please reply to list if it's a mailing list post - http://shlom.in/reply .
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Help with script How to prepend 2 lines instead of 1
On 20/01/2011 19:10, steve1040 wrote:
Using the script below I need to add a second line with the following
text:
STAGEHDR|Barcoded
#!perl
use strict;
use warnings;
my $file = 'path/to/Access.csv';
my $newline = ENTHDR|1|3.0;
{
local @ARGV = ($file);
local $^I = '.bac';
while(){
if ($. == 1) {
print $newline$/;
}
else {
print;
}
}
}
Hi Steve
You seem to have ignored the help you were offered when you last posted
this problem. The code you have here (apart from the misgivings that
Shlomi has expressed) will /replace/ the first line of the input file
with the given string. Is that what you want, or do you need to add
(prepend) them as you said previously? You have already been shown code
that will do the latter; do you need a different solution?
- Rob
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
AW:FW: 1--.
Dear, I have tried to purchase some products from a business company, I have attracted by high quality products, low price and enthusiastic services, I think if you are free, you can go to see: styleele.com ,picking your interesting. ~--. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Can't use string 1 as HASH ref while strict refs in use
On 20 July 2010 04:40, Mimi Cafe mimic...@googlemail.com wrote:
I passed a has reference to my sub and tried dereferencing it within the sub
and get an exception Can't use string (1) as HASH ref while strict refs in
use.
my %mail_parameters = (
'Fname' = $nickname_db_exist[1],
'Lname' = $nickname_db_exist[2],
'E-mail' = $reset_email,
'Subject' = Your $site_name Password Reset,
);
# Send the requested information.
Mail_worker(\%mail_parameters);
Sub mail_worker {
$received_arg = @_;
%params = %$received_arg;# Can't use string 1 as HASH ref while strict
refs in use
.
..
I hope Uri will forgive me but I will expand a little.
$received_arg = @_;
You want to shift the argument list but you are actually assigned the
argument array to a scalar value and that will render it's size (1).
You passed Mail_worker a reference to a hash so that hash is now a
single scalar value. Then in your subroutine (called mail_worker, you
dropped the case in your example) after assigning the length of the
argument list to $recieved_arg you attempt to deference it, causing
the error. You could have kept the hash as a reference
sub Mail_worker {
my $recieved_arg = shift;
print User first name is $recieved_arg-{Fname}\n;
.
}
You could have kept it as a hash but that's passing by value and
considered slightly poor practice as your passing more data that you
need. One more option would be to use a named parameter list
Mail_worker(Fname = $nickname_db_exist[1],
Lname = $nickname_db_exist[2],
'E-mail' = $reset_email,
'Subject' = Your $site_name Password Reset,
);
sub Mail_worker {
my %args = @_
print User first name is $recieved_arg{Fname}\n
}
I hope that helps,
Dp.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
RE: Can't use string 1 as HASH ref while strict refs in use
Oh, yes! I see. I went through the codes several times but did not pick that mistake for some reason. Perhaps I was working too late in the night :-) This works: $received_arg = shift; Thanks = -Original Message- = From: Uri Guttman [mailto:u...@stemsystems.com] = Sent: 20 July 2010 04:44 = To: Mimi Cafe = Cc: 'Perl Beginners' = Subject: Re: Can't use string 1 as HASH ref while strict refs in use = = MC == Mimi Cafe mimic...@googlemail.com writes: = = MC $received_arg = @_; = = read perldoc perldata and see what happens when you assign an array to = a = scalar. you don't get what you think you are getting. context is VERY = important to learn in perl and this is a critical context situation = that = is very common. i won't give you the answer since reading about it = will = strengthten your learning about this. = = uri = = -- = Uri Guttman -- u...@stemsystems.com = http://www.sysarch.com -- = - Perl Code Review , Architecture, Development, Training, Support = -- = - Gourmet Hot Cocoa Mix http://bestfriendscocoa.com -- = --- -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Can't use string 1 as HASH ref while strict refs in use
D == Dermot paik...@gmail.com writes: D I hope Uri will forgive me but I will expand a little. partially forgive! :) D $received_arg = @_; D You want to shift the argument list but you are actually assigned the D argument array to a scalar value and that will render it's size (1). D You passed Mail_worker a reference to a hash so that hash is now a D single scalar value. Then in your subroutine (called mail_worker, you D dropped the case in your example) after assigning the length of the D argument list to $recieved_arg you attempt to deference it, causing D the error. You could have kept the hash as a reference why do you say she wants to shift @_? that is the lesser style of getting an arg from @_. the better way IMNSHO is assigning to a list. shift is slower, doesn't work well for multiple args (one shift per statement) and it modifies @_ unnecessarily. there are times when it is useful but the primary method should be a list assignment. uri -- Uri Guttman -- u...@stemsystems.com http://www.sysarch.com -- - Perl Code Review , Architecture, Development, Training, Support -- - Gourmet Hot Cocoa Mix http://bestfriendscocoa.com - -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Can't use string 1 as HASH ref while strict refs in use
I passed a has reference to my sub and tried dereferencing it within the sub
and get an exception Can't use string (1) as HASH ref while strict refs in
use.
my %mail_parameters = (
'Fname' = $nickname_db_exist[1],
'Lname' = $nickname_db_exist[2],
'E-mail' = $reset_email,
'Subject' = Your $site_name Password Reset,
);
# Send the requested information.
Mail_worker(\%mail_parameters);
Sub mail_worker {
$received_arg = @_;
%params = %$received_arg;# Can't use string 1 as HASH ref while strict
refs in use
.
..
}
Regards
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Can't use string 1 as HASH ref while strict refs in use
MC == Mimi Cafe mimic...@googlemail.com writes: MC $received_arg = @_; read perldoc perldata and see what happens when you assign an array to a scalar. you don't get what you think you are getting. context is VERY important to learn in perl and this is a critical context situation that is very common. i won't give you the answer since reading about it will strengthten your learning about this. uri -- Uri Guttman -- u...@stemsystems.com http://www.sysarch.com -- - Perl Code Review , Architecture, Development, Training, Support -- - Gourmet Hot Cocoa Mix http://bestfriendscocoa.com - -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: \1 in character class?
Wow, an impressive set of responses -- thanks Erez, Chas, Chris, C., Shawn, and Jennifer. I think most of the response pointed to non-greedy matches, is that right? Are those deprecated or discouraged? Thanks again. - Bryan On Wed, Jul 14, 2010 at 00:50, C.DeRykus dery...@gmail.com wrote: snip s/(\w+)\s/$1nbsp;/g; snip Neat. Using the \K construct available in 5.10, you can even eliminate the need for the capture: s/ \w+ \K \s /nbsp;/gx; snip Yeah, but both of these are fragile, the following string won't work: data: this, is a string more: this is another -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: \1 in character class?
BRH == Bryan R Harris bryan_r_har...@raytheon.com writes: BRH I think most of the response pointed to non-greedy matches, is BRH that right? Are those deprecated or discouraged? nope, they are very useful and stable (not experimental in the least). non-greedy vs greedy is one of those things that newbies almost never seem to find on their own but get it when told about them. this is why i keep saying to rtfm all the regex docs as there is a host of useful easy to learn things in them. when i say docs, i mean perlrequick, perlretut and perlre. each has a different target but all are useful. and when you read a doc for the first time (or repeat times) read it ALL the way through and skip/skim the parts you may not get. just knowing about a feature a little and before you ever use it helps when you really need it. non-greedy is well documented but you have to read about it. uri -- Uri Guttman -- u...@stemsystems.com http://www.sysarch.com -- - Perl Code Review , Architecture, Development, Training, Support -- - Gourmet Hot Cocoa Mix http://bestfriendscocoa.com - -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: \1 in character class?
On Jul 14, 2:59 pm, chas.ow...@gmail.com (Chas. Owens) wrote: On Wed, Jul 14, 2010 at 00:50, C.DeRykus dery...@gmail.com wrote: snip s/(\w+)\s/$1nbsp;/g; snip Neat. Using the \K construct available in 5.10, you can even eliminate the need for the capture: s/ \w+ \K \s /nbsp;/gx; snip Yeah, but both of these are fragile, the following string won't work: data: this, is a string more: this is another Agreed this isn't the most robust but there wasn't a complete spec so simple quoted string might throw someone. And I notice the OP's original despace sub for instance contained: s/\s/nbsp;/g; But, one of the solutions morphed that to: s/ /nbsp;/g which, might or might not, be right either. -- Charles DeRykus -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: \1 in character class?
- Original Message -
From: Bryan R Harris bryan_r_har...@raytheon.com
Subject: \1 in character class?
I'm trying to temporarily deal with simple quoted strings by turning:
data: this is a string more: this is another
into...
data: thisnbsp;isnbsp;anbsp;string more: thisnbsp;isnbsp;another
TIA.
- Bryan
Here is a way using tbe module Regexp::Common.
#!/usr/bin/perl
use strict;
use warnings;
use Regexp::Common;
while (DATA) {
s/($RE{quoted})/ (my $s=$1) =~ s[\s][nbsp;]g; $s/egx;
print;
}
__DATA__
data: this is a string more: this is another
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: \1 in character class?
On Jul 13, 8:09 am, jonesharring...@gmail.com (Jennifer Jones Harrington) wrote: How about... #!/usr/bin/perl use warnings; $_ = data: \this is a string\ more: \this is another\; s/(\w+)\s/$1nbsp;/g; print $_\n; It prints: data: thisnbsp;isnbsp;anbsp;string more: thisnbsp;isnbsp;another Neat. Using the \K construct available in 5.10, you can even eliminate the need for the capture: s/ \w+ \K \s /nbsp;/gx; -- Charles DeRykus s/ -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: \1 in character class?
On Wed, Jul 14, 2010 at 00:50, C.DeRykus dery...@gmail.com wrote: snip s/(\w+)\s/$1nbsp;/g; snip Neat. Using the \K construct available in 5.10, you can even eliminate the need for the capture: s/ \w+ \K \s /nbsp;/gx; snip Yeah, but both of these are fragile, the following string won't work: data: this, is a string more: this is another -- Chas. Owens wonkden.net The most important skill a programmer can have is the ability to read. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
\1 in character class?
I'm trying to temporarily deal with simple quoted strings by turning:
data: this is a string more: this is another
into...
data: thisnbsp;isnbsp;anbsp;string more: thisnbsp;isnbsp;another
I thought this would work:
s/(['])([^\1]*)\1/${1}.despace($2).$1/gse;
sub despace {
my $t = shift;
$t =~ s/\s/nbsp;/g;
return $t;
}
... but it doesn't. It looks like the [^\1]* in the regex isn't working
right.
I can always split it into two, but I'm curious why the above doesn't work.
TIA.
- Bryan
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: \1 in character class?
How about...
#!/usr/bin/perl
use warnings;
$_ = data: \this is a string\ more: \this is another\;
s/(\w+)\s/$1nbsp;/g;
print $_\n;
It prints:
data: thisnbsp;isnbsp;anbsp;string more: thisnbsp;isnbsp;another
On Tue, Jul 13, 2010 at 6:00 AM, Bryan R Harris bryan_r_har...@raytheon.com
wrote:
I'm trying to temporarily deal with simple quoted strings by turning:
data: this is a string more: this is another
into...
data: thisnbsp;isnbsp;anbsp;string more: thisnbsp;isnbsp;another
I thought this would work:
s/(['])([^\1]*)\1/${1}.despace($2).$1/gse;
sub despace {
my $t = shift;
$t =~ s/\s/nbsp;/g;
return $t;
}
... but it doesn't. It looks like the [^\1]* in the regex isn't working
right.
I can always split it into two, but I'm curious why the above doesn't work.
TIA.
- Bryan
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: \1 in character class?
On 10-07-13 06:00 AM, Bryan R Harris wrote:
I'm trying to temporarily deal with simple quoted strings by turning:
data: this is a string more: this is another
into...
data: thisnbsp;isnbsp;anbsp;string more: thisnbsp;isnbsp;another
I thought this would work:
s/(['])([^\1]*)\1/${1}.despace($2).$1/gse;
sub despace {
my $t = shift;
$t =~ s/\s/nbsp;/g;
return $t;
}
... but it doesn't. It looks like the [^\1]* in the regex isn't working
right.
I can always split it into two, but I'm curious why the above doesn't work.
Because [] define a character set; everything inside it is a character.
That means it does not expand \1.
Try:
s/(['])(.*?)\1/${1}.despace($2).$1/gse;
This will set $2 to the minimum number of characters between the quotes.
For details, see:
perldoc perlretut
perldoc perlre
--
Just my 0.0002 million dollars worth,
Shawn
Programming is as much about organization and communication
as it is about coding.
The secret to great software: Fail early often.
Eliminate software piracy: use only FLOSS.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: \1 in character class?
On 13 July 2010 13:00, Bryan R Harris bryan_r_har...@raytheon.com wrote:
I thought this would work:
s/(['])([^\1]*)\1/${1}.despace($2).$1/gse;
... but it doesn't. It looks like the [^\1]* in the regexp isn't working
right.
Character classes (characters inside square brackets - []) in regexp
notation, interpret whatever is inside sometimes differently than it
would be interpreted otherwise, with backslash taking a different
meaning so \1,\2 back-references doesn't have the special meaning it
has outside of the square brackets. There are other hijinks regarding
backspace functionality inside character classes, which are
sporadically documented in the different regexp descriptions and
manuals.
For what you need, I suggest a negative lookahead, i.e. (?!\1) for
zero-length lookahead.
--
Erez
Observations, not opinions
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: \1 in character class?
On Tue, Jul 13, 2010 at 06:00, Bryan R Harris
bryan_r_har...@raytheon.com wrote:
I'm trying to temporarily deal with simple quoted strings by turning:
data: this is a string more: this is another
into...
data: thisnbsp;isnbsp;anbsp;string more: thisnbsp;isnbsp;another
I thought this would work:
s/(['])([^\1]*)\1/${1}.despace($2).$1/gse;
sub despace {
my $t = shift;
$t =~ s/\s/nbsp;/g;
return $t;
}
... but it doesn't. It looks like the [^\1]* in the regex isn't working
right.
I can always split it into two, but I'm curious why the above doesn't work.
\1 in a character class does work, it just doesn't mean what you think it means:
perl -le 'print chr(1) =~ /[\1]/ ? match : no_match'
In a character class, escaped numbers 1-7, 10-77, 100-777, and 001-777
are octal escapes that are replaced with the character whose ordinal
number is the escaped value (in octal), so \12 is \012 is \x{0a} is
ord(10) is linefeed in ASCII. Outside of a character class in a
regex, the escaped numbers 1 - 9 refer to either captures if there are
that many captures or an octal escape if there aren't that many
captures. So, in /(a)\1/ the \1 refers the value of the first
capture, but /a\1/ matches a followed by chr(1) (start of header in
ASCII). Octal escapes really shouldn't be used anymore since we have
the \x{NUM} quoting mechanism is much more flexible. As for
backreferences, if you are using Perl 5.10 or later you have \g{N}:
\g{N} replaces \N for backreferences and has the added benefit that
\g{-1} refers to the last capture before it, \g{-2} referes to the
next to last capture before it, and so on. This means that
/(a)\g{-1}(b)\g{-2}\g{-1}/ is the same as /aabab/.
To make your substitution work, you need to say
#!/usr/bin/perl
use strict;
use warnings;
my $s = 'data: this is a string more: this is another';
$s =~ s{
(.*?)
}{
my $temp = $1;
$temp =~ s/ /nbsp;/g;
qq/$temp/;
}xgse;
print $s\n;
or the more compact:
#!/usr/bin/perl
use strict;
use warnings;
sub despace {
my $s = shift;
$s =~ s/ /nbsp;/g;
return $s;
}
my $s = 'data: this is a string more: this is another';
$s =~ s/(.*?)/despace qq{$1}/gse;
print $s\n;
--
Chas. Owens
wonkden.net
The most important skill a programmer can have is the ability to read.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: \1 in character class?
On 13 July 2010 18:16, Shawn H Corey shawnhco...@gmail.com wrote: Because [] define a character set; everything inside it is a character. That means it does not expand \1. That's not entirely correct. Character classes recognize variables, escaped characters and some other regexp notation, but not \1 back-references -- Erez Observations, not opinions -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: \1 in character class?
On Jul 13, 2010, at 11:32, Erez Schatz moonb...@gmail.com wrote: On 13 July 2010 18:16, Shawn H Corey shawnhco...@gmail.com wrote: Because [] define a character set; everything inside it is a character. That means it does not expand \1. That's not entirely correct. Character classes recognize variables, escaped characters and some other regexp notation, but not \1 back-references -- Erez Observations, not opinions -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/ It does recognize them, it just recognizes them as octal escapes. [\8] is even more fun. It matches chr(0) or the character 8. There is some work going on in perl 5.13 to fix this (or at least give a better warning message). -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
What is the difference between: 'my $var = 1' vs. 'my ( $var ) = 1'?
At the introductory level it seems like I have often seen code like this: use strict; my $var = 1; And as I review other peoples' scripts I have often encountered code like this: use strict; my ( $this, $that, $the_other ); Which I interpreted as a mechanism to declare a number of scalar variables with a minimum of typing. But lately I've been seeing this syntax and I was wondering if it was fundamentally different (and somehow more desirable): use strict; my ( $var ) = 1; As if $var is being declared in a list context; what, if anything, do I get by including parentheses when declaring a single variable? Thanks, --Marc
Re: What is the difference between: 'my $var = 1' vs. 'my ( $var ) = 1'?
On Tue, Apr 20, 2010 at 2:23 PM, Marc Perry marcperrys...@gmail.com wrote: As if $var is being declared in a list context; what, if anything, do I get by including parentheses when declaring a single variable? I'm new to this myself, but it appears to alter the context of the statement. Take the following: #!/usr/bin/env perl use strict; use warnings; $, = $\ = \n; my @a = (element1, element2, element3); my $x = @a; my ( $y ) = @a; print $x, $y; # EOF The output should be: 3 element1 In the first case, the context is scalar, which results in the element count being assigned to $x instead of the element(s). In the second case, the context is list context, I think, which results in the first element of the array being assigned to the variable $y. I'm not clear on how to properly explain this, but to me it appears to make a list of lvalues (assignables) and then moves the data from corresponding positions on the right side of the equals sign to the left. Again, there's probably a much better (and more correct) way to explain that. ;) In other words, using or not using parenthesis can be context sensitive so you need to know what you're doing with it. If you're just declaring a normal variable, as in your example where you assign it 1, then it doesn't seem to technically matter which you use, but you're probably preferred to NOT use parenthesis because it's unnecessary and might even be confusing if you are (and if the context of the right-side changes then the meaning will change). ??? `perldoc perldata' appears to cover context somewhat: http://perldoc.perl.org/perldata.html#Context -- Brandon McCaig bamcc...@gmail.com V zrna gur orfg jvgu jung V fnl. Vg qbrfa'g nyjnlf fbhaq gung jnl. Castopulence Software http://www.castopulence.org/ bamcc...@castopulence.org -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: What is the difference between: 'my $var = 1' vs. 'my ( $var ) = 1'?
On 4/20/10 Tue Apr 20, 2010 11:23 AM, Marc Perry marcperrys...@gmail.com scribbled: At the introductory level it seems like I have often seen code like this: use strict; my $var = 1; And as I review other peoples' scripts I have often encountered code like this: use strict; my ( $this, $that, $the_other ); Which I interpreted as a mechanism to declare a number of scalar variables with a minimum of typing. But lately I've been seeing this syntax and I was wondering if it was fundamentally different (and somehow more desirable): use strict; my ( $var ) = 1; As if $var is being declared in a list context; what, if anything, do I get by including parentheses when declaring a single variable? You put the left-hand side into list context, which forces the right-hand side of the assignment into list context. Perl will interpolate the scalar value 1 into a list for you, yielding the one-element list (1). The first element of the right-hand side (1) will then be assigned to the first element of the left-hand side ($var). Therefore, you gain nothing except to confuse your readers. That line is better written as: my $var = 1; -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: 1-line datafile, need data for another routine
Rob Dixon wrote:
Chris Coggins wrote:
I posted a question to this list yesterday from the google groups
interface, asking for help with the following. I have since tried to
post additional details in replies to that message using the google
groups site and none of my posts have shown up on the list so let's
try this again the right way.
I have a datafile with 1 line of data, 30 numbers delimited by
tildes. (Sample code below only uses 4 numbers to save time)
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
I neglected to mention in my original post that I need to access
these new values elsewhere in the script to perform additional math
functions with them.
I've tried several variations of the code below, including using
arrays, and none of them got through without the script failing. The
new datafile gets written, but it merely contains a ~. The errors I
get are use of uninitialized values in such and such line and
variables needs explicit package name. When the script does run,
the variables lose their values as soon as I close the file after
inhaling it, making all the rest of the actions in the subroutine
futile.
the datafile used below initially contains 30 values that were
written previously, and this has been verified over and over.
sub newValues {
my($file) = shift;
open(FILE, $file) or die(Unable to open data file.);
while (FILE) {
my($a,$b,$c,$d) = split(/~/, $_);
$a = $a+$previousarray[4]; # I've tried to perform this math action
after close(FILE) and get the same result - failure.
$b = $b+$previousarray[7];
$c = $c+$previousarray[0];
}
close(FILE);
open(FILE, $file) || die (unable to open file);
print FILE ($a~$b~$c \n);
close(FILE);
}
#end sub
Now my datafile just contains a single tilde and no values. I've also
tried to bring the original data from the datafile into my(@array)
and get the same errors.
Keep in mind I need other subroutines to be able use these new
values, but these local variables lose their values once the file is
closed. I've also tried to declare them as global variables but I'm
not doing something right because the script won't execute.
I really need some help figuring this out if somebody would be kind
enough to help a novice.
Hello Chris
Your lexical variables $a, $b, $c are local to the 'while' block, and
do not exist outside it. Error Global symbol xx requires explicit
package name is because the variable is not declared. Error Use of
uninitialized value... is because Perl uses a value of 'undef' where
variables are missing.
As an aside it is bad form to use meaningless variable names, and $a
and $b are special names that are used by core Perl so should be
avoided. Also it is prefereable to use lexical file handles and the
three-argument form of 'open', and incorporating the standard variable
$! into the die string will give valuable information about why the
operation failed.
Declaring your variables outside the 'while' loop would fix your
problem, but as you are interested only in the first line of the file
it is as well to remove the loop altogether. Take a look at the code
below and see if it meets your requirements.
HTH,
Rob
sub newValues {
my $file = shift;
open my $data, '', $file or die Unable to open data file: $!;
my $line = $data;
close $data;
my @data = split /~/, $line;
die Invalid data format if @data 3;
$data[0] += $previousarray[4];
$data[1] += $previousarray[7];
$data[2] += $previousarray[0];
open my $out, '', $file or die Unable to open output file: $!;
print $out join('~', @data[0,1,2]), \n;
close $out or die Failed to close output file: $!;
}
Rob, thank you very much. This worked perfectly, unless my datafile is
empty at the start. Easiest fix was inserting 30 zero-tildes into the file.
I have a couple other snags if yall are willing to tolerate the questions.
1. another script uses data passed into it from an html form. Some of
the fields are empty, and my print report file subroutine prints the
empty variables because I don't know how to filter them out, and they
need to be removed from the report. Can someone give me the perfectly
formed if statement that lets me skip over the one or two empty
variables during the print action? The data being printed to the file is
stored in an array. See code below.
print FILE (Report summary: $taskarray[0] \n); #this value is good
print FILE (Data for task 3: $taskarray[3] \n); #this value is good
print FILE (Data for task 7: $taskarray[7] \n); #this value is empty,
don't print this data
print FILE (Data for task 2: $taskarray[2] \n); #this value is empty,
don't print this data
print FILE (Data for task 11: $taskarray[11] \n); #this value is good
but needs to be modified, see #2 below
2. Some of the data being
Re: 1-line text file with numbers, need to add to them
On 2/4/10, Chris cacogg...@gmail.com wrote:
On Feb 4, 10:59 am, shlo...@iglu.org.il (Shlomi Fish) wrote:
Hi Chris!
Have you visitedhttp://perl-begin.org/yet and read a good introductory
book
or tutorial?
On Thursday 04 Feb 2010 09:27:32 Chris wrote:
I need some help with this problem.
I've got a text file datafile with 1 line of data comprised of 30
different numbers delimited with ~s.
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
I have tried for two days to figure out what I'm doing wrong, but I
keep getting needs a package name errors for every variable
nomenclature I try to work with. I've declare arrays and variables
until my fingers are numb and nothing is working. I'm using Perl 5.008
if that matters.
You need to declare variables using my. Can you show us what you have so
far?
Regards,
Shlomi Fish
Can somebody please help?
Yes I have read several tutorials, and have a basic understanding of
how to open a file and read the data into an array. The problem I run
into is that once I close the file and perform my math functions and
re-open the file to write the data to, the data is gone. Empty values
are written to the file, making the file itself empty. I need to know
the proper nomenclature for the arrays and variables so that the
values of variables/elements are static for the next action. Here's
one of the methods I tried to use that failed:
#open file, get data, close file
open(FILE, datafile.txt) or die(Unable to open data file.);
while (FILE) {
my($a,$b,$c) = split(/~/, $_);
}
close(FILE);
#perform math
$a = $a+$previousarray[0]; #add the value of $a and the value of
an element in a previous array
$b = $b+$previousarray[1];
$c = $c+$previousarray[2];
#write new values to the datafile
open(FILE, datafile.txt) or die (unable to open file.);
print FILE ($a~);
print FILE ($b~);
print FILE ($c~);
close(FILE);
#end of problem section
The above produces an empty datafile. I have tried to declare an
explicit array for the file data using the following:
open(FILE, datafile.txt) or die(Unable to open data file.);
@values=FILE;
close(FILE);
foreach $element (@values)
{
($a,$b,$c) = split(/~/, $element);
$a = $a+$previousarray[0];
$b = $b+$previousarray[1];
$c = $c+$previousarray[2];
#then open the datafile and write new values.
I keep getting use of unititialized values errors, and needs
explicit package name errors, and an empty datafile.
That's why I came to this forum for help. I also neglected to note in
my original post that I need to access these new values elsewhere in
the script.
I'm not sure why you write the new values to a file. You could leave
the new values in an array, then later in your program you could
retrieve the new values from the array.
data1.txt
0~s10~s100
use strict;
use warnings;
use 5.010;
open my $IN_FILE, '', 'data1.txt'
or die couldn't open data1.txt for reading: $!;
chomp (my $line = $IN_FILE);
close $IN_FILE;
my @numbers = split /~s/, $line;
say @numbers; #0 10 100
for (@numbers) {
$_ += 1;
}
say @numbers; #1 11 101
my $output = join '~s', @numbers;
say $output; #1~s11~s101
open my $OUT_FILE, '', 'data1.txt'
or die couldn't open data1.txt for writing: $!;
say $OUT_FILE $output;
close $OUT_FILE;
data1.txt
-
1~s11~s101
print() is your friend.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line datafile, need data for another routine
On 2/6/10, Chris Coggins cacogg...@cox.net wrote:
Rob Dixon wrote:
Chris Coggins wrote:
I posted a question to this list yesterday from the google groups
interface, asking for help with the following. I have since tried to
post additional details in replies to that message using the google
groups site and none of my posts have shown up on the list so let's
try this again the right way.
I have a datafile with 1 line of data, 30 numbers delimited by
tildes. (Sample code below only uses 4 numbers to save time)
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
I neglected to mention in my original post that I need to access
these new values elsewhere in the script to perform additional math
functions with them.
I've tried several variations of the code below, including using
arrays, and none of them got through without the script failing. The
new datafile gets written, but it merely contains a ~. The errors I
get are use of uninitialized values in such and such line and
variables needs explicit package name. When the script does run,
the variables lose their values as soon as I close the file after
inhaling it, making all the rest of the actions in the subroutine
futile.
the datafile used below initially contains 30 values that were
written previously, and this has been verified over and over.
sub newValues {
my($file) = shift;
open(FILE, $file) or die(Unable to open data file.);
while (FILE) {
my($a,$b,$c,$d) = split(/~/, $_);
$a = $a+$previousarray[4]; # I've tried to perform this math action
after close(FILE) and get the same result - failure.
$b = $b+$previousarray[7];
$c = $c+$previousarray[0];
}
close(FILE);
open(FILE, $file) || die (unable to open file);
print FILE ($a~$b~$c \n);
close(FILE);
}
#end sub
Now my datafile just contains a single tilde and no values. I've also
tried to bring the original data from the datafile into my(@array)
and get the same errors.
Keep in mind I need other subroutines to be able use these new
values, but these local variables lose their values once the file is
closed. I've also tried to declare them as global variables but I'm
not doing something right because the script won't execute.
I really need some help figuring this out if somebody would be kind
enough to help a novice.
Hello Chris
Your lexical variables $a, $b, $c are local to the 'while' block, and
do not exist outside it. Error Global symbol xx requires explicit
package name is because the variable is not declared. Error Use of
uninitialized value... is because Perl uses a value of 'undef' where
variables are missing.
As an aside it is bad form to use meaningless variable names, and $a
and $b are special names that are used by core Perl so should be
avoided. Also it is prefereable to use lexical file handles and the
three-argument form of 'open', and incorporating the standard variable
$! into the die string will give valuable information about why the
operation failed.
Declaring your variables outside the 'while' loop would fix your
problem, but as you are interested only in the first line of the file
it is as well to remove the loop altogether. Take a look at the code
below and see if it meets your requirements.
HTH,
Rob
sub newValues {
my $file = shift;
open my $data, '', $file or die Unable to open data file: $!;
my $line = $data;
close $data;
my @data = split /~/, $line;
die Invalid data format if @data 3;
$data[0] += $previousarray[4];
$data[1] += $previousarray[7];
$data[2] += $previousarray[0];
open my $out, '', $file or die Unable to open output file: $!;
print $out join('~', @data[0,1,2]), \n;
close $out or die Failed to close output file: $!;
}
Rob, thank you very much. This worked perfectly, unless my datafile is
empty at the start. Easiest fix was inserting 30 zero-tildes into the file.
I have a couple other snags if yall are willing to tolerate the questions.
1. another script uses data passed into it from an html form. Some of
the fields are empty, and my print report file subroutine prints the
empty variables because I don't know how to filter them out, and they
need to be removed from the report. Can someone give me the perfectly
formed if statement that lets me skip over the one or two empty
variables during the print action? The data being printed to the file is
stored in an array. See code below.
print FILE (Report summary: $taskarray[0] \n); #this value is good
print FILE (Data for task 3: $taskarray[3] \n); #this value is good
print FILE (Data for task 7: $taskarray[7] \n); #this value is empty,
don't print this data
print FILE (Data for task 2: $taskarray[2] \n); #this value is empty,
don't print this data
print FILE (Data for task 11: $taskarray[11] \n
Re: 1-line datafile, need data for another routine
At 5:48 AM -0500 2/6/10, Chris Coggins wrote:
1. another script uses data passed into it from an html form. Some
of the fields are empty, and my print report file subroutine
prints the empty variables because I don't know how to filter them
out, and they need to be removed from the report. Can someone give
me the perfectly formed if statement that lets me skip over the
one or two empty variables during the print action? The data being
printed to the file is stored in an array. See code below.
print FILE (Report summary: $taskarray[0] \n); #this value is good
print FILE (Data for task 3: $taskarray[3] \n); #this value is good
print FILE (Data for task 7: $taskarray[7] \n); #this value is
empty, don't print this data
print FILE (Data for task 2: $taskarray[2] \n); #this value is
empty, don't print this data
print FILE (Data for task 11: $taskarray[11] \n); #this value is
good but needs to be modified, see #2 below
If a scalar variable is empty, i.e. is either undef or an empty
string '', it will have a false value in a logical expression.
Therefore, you can test the value of the variable and only print it
if it is true:
if( $string ) {
print $string\n;
}
or the shorter equivalent:
print $string\n if $string;
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line datafile, need data for another routine
I posted a question to this list yesterday from the google groups
interface, asking for help with the following. I have since tried to
post additional details in replies to that message using the google
groups site and none of my posts have shown up on the list so let's try
this again the right way.
I have a datafile with 1 line of data, 30 numbers delimited by tildes.
(Sample code below only uses 4 numbers to save time)
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
I neglected to mention in my original post that I need to access these
new values elsewhere in the script to perform additional math functions
with them.
I've tried several variations of the code below, including using arrays,
and none of them got through without the script failing. The new
datafile gets written, but it merely contains a ~. The errors I get are
use of uninitialized values in such and such line and variables needs
explicit package name. When the script does run, the variables lose
their values as soon as I close the file after inhaling it, making all
the rest of the actions in the subroutine futile.
the datafile used below initially contains 30 values that were written
previously, and this has been verified over and over.
sub newValues {
my($file) = shift;
open(FILE, $file) or die(Unable to open data file.);
while (FILE) {
my($a,$b,$c,$d) = split(/~/, $_);
$a = $a+$previousarray[4]; # I've tried to perform this math action
after close(FILE) and get the same result - failure.
$b = $b+$previousarray[7];
$c = $c+$previousarray[0];
}
close(FILE);
open(FILE, $file) || die (unable to open file);
print FILE ($a~$b~$c \n);
close(FILE);
}
#end sub
Now my datafile just contains a single tilde and no values. I've also
tried to bring the original data from the datafile into my(@array) and
get the same errors.
Keep in mind I need other subroutines to be able use these new values,
but these local variables lose their values once the file is closed.
I've also tried to declare them as global variables but I'm not doing
something right because the script won't execute.
I really need some help figuring this out if somebody would be kind
enough to help a novice.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line text file with numbers, need to add to them
On Feb 4, 10:59 am, shlo...@iglu.org.il (Shlomi Fish) wrote:
Hi Chris!
Have you visitedhttp://perl-begin.org/yet and read a good introductory book
or tutorial?
On Thursday 04 Feb 2010 09:27:32 Chris wrote:
I need some help with this problem.
I've got a text file datafile with 1 line of data comprised of 30
different numbers delimited with ~s.
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
I have tried for two days to figure out what I'm doing wrong, but I
keep getting needs a package name errors for every variable
nomenclature I try to work with. I've declare arrays and variables
until my fingers are numb and nothing is working. I'm using Perl 5.008
if that matters.
You need to declare variables using my. Can you show us what you have so
far?
Regards,
Shlomi Fish
Can somebody please help?
Yes I have read several tutorials, and have a basic understanding of
how to open a file and read the data into an array. The problem I run
into is that once I close the file and perform my math functions and
re-open the file to write the data to, the data is gone. Empty values
are written to the file, making the file itself empty. I need to know
the proper nomenclature for the arrays and variables so that the
values of variables/elements are static for the next action. Here's
one of the methods I tried to use that failed:
#open file, get data, close file
open(FILE, datafile.txt) or die(Unable to open data file.);
while (FILE) {
my($a,$b,$c) = split(/~/, $_);
}
close(FILE);
#perform math
$a = $a+$previousarray[0]; #add the value of $a and the value of
an element in a previous array
$b = $b+$previousarray[1];
$c = $c+$previousarray[2];
#write new values to the datafile
open(FILE, datafile.txt) or die (unable to open file.);
print FILE ($a~);
print FILE ($b~);
print FILE ($c~);
close(FILE);
#end of problem section
The above produces an empty datafile. I have tried to declare an
explicit array for the file data using the following:
open(FILE, datafile.txt) or die(Unable to open data file.);
@values=FILE;
close(FILE);
foreach $element (@values)
{
($a,$b,$c) = split(/~/, $element);
$a = $a+$previousarray[0];
$b = $b+$previousarray[1];
$c = $c+$previousarray[2];
#then open the datafile and write new values.
I keep getting use of unititialized values errors, and needs
explicit package name errors, and an empty datafile.
That's why I came to this forum for help. I also neglected to note in
my original post that I need to access these new values elsewhere in
the script. This specific action (open file, get data, perform math,
write data) occurs in a subroutine in a much larger script, and I need
to use these values in other subroutines in the script. But that's not
the main problem yet. The main problem that prompted me to ask the
question in the first place is getting this portion to work correctly
so that I have the correct values in the datafile after these actions
are performed.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line text file with numbers, need to add to them
For instance, the below is your data file --data.txt
12~s1~s314~s5677~s899~s0~s
Here are the codes:
#!/usr/bin/perl
open(DATA,data.txt);
while(DATA) {
$number=$_;
# print $number;
while ($number =~ /([0-9]+)~s/g){
printf (%d\n,$1);
}
}
close(DATA);
On Feb 4, 7:27 am, cacogg...@gmail.com (Chris) wrote:
I need some help with this problem.
I've got a text file datafile with 1 line of data comprised of 30
different numbers delimited with ~s.
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
I have tried for two days to figure out what I'm doing wrong, but I
keep getting needs a package name errors for every variable
nomenclature I try to work with. I've declare arrays and variables
until my fingers are numb and nothing is working. I'm using Perl 5.008
if that matters.
Can somebody please help?
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line text file with numbers, need to add to them
Hi Frank!
On Thursday 04 Feb 2010 19:24:41 Frank wrote:
For instance, the below is your data file --data.txt
12~s1~s314~s5677~s899~s0~s
Here are the codes:
#!/usr/bin/perl
open(DATA,data.txt);
while(DATA) {
$number=$_;
# print $number;
while ($number =~ /([0-9]+)~s/g){
printf (%d\n,$1);
}
}
close(DATA);
This code snippet is wrong on so many levels:
1. No use strict; and no use warnings.
2. No three-args open , lexical filehandles and a trailing or die.
Why did you post this to the list, possibly misleading other people, when you
don't know the Modern Perl conventions?
Regards,
Shlomi Fish
--
-
Shlomi Fish http://www.shlomifish.org/
Interview with Ben Collins-Sussman - http://shlom.in/sussman
Deletionists delete Wikipedia articles that they consider lame.
Chuck Norris deletes deletionists whom he considers lame.
Please reply to list if it's a mailing list post - http://shlom.in/reply .
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line datafile, need data for another routine
Chris Coggins wrote:
I posted a question to this list yesterday from the google groups
interface, asking for help with the following. I have since tried to
post additional details in replies to that message using the google
groups site and none of my posts have shown up on the list so let's try
this again the right way.
I have a datafile with 1 line of data, 30 numbers delimited by tildes.
(Sample code below only uses 4 numbers to save time)
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
I neglected to mention in my original post that I need to access these
new values elsewhere in the script to perform additional math functions
with them.
I've tried several variations of the code below, including using arrays,
and none of them got through without the script failing. The new
datafile gets written, but it merely contains a ~. The errors I get are
use of uninitialized values in such and such line and variables needs
explicit package name. When the script does run, the variables lose
their values as soon as I close the file after inhaling it, making all
the rest of the actions in the subroutine futile.
the datafile used below initially contains 30 values that were written
previously, and this has been verified over and over.
sub newValues {
my($file) = shift;
open(FILE, $file) or die(Unable to open data file.);
while (FILE) {
my($a,$b,$c,$d) = split(/~/, $_);
$a = $a+$previousarray[4]; # I've tried to perform this math action
after close(FILE) and get the same result - failure.
$b = $b+$previousarray[7];
$c = $c+$previousarray[0];
}
close(FILE);
open(FILE, $file) || die (unable to open file);
print FILE ($a~$b~$c \n);
close(FILE);
}
#end sub
Now my datafile just contains a single tilde and no values. I've also
tried to bring the original data from the datafile into my(@array) and
get the same errors.
Keep in mind I need other subroutines to be able use these new values,
but these local variables lose their values once the file is closed.
I've also tried to declare them as global variables but I'm not doing
something right because the script won't execute.
I really need some help figuring this out if somebody would be kind
enough to help a novice.
Hello Chris
Your lexical variables $a, $b, $c are local to the 'while' block, and do
not exist outside it. Error Global symbol xx requires explicit package
name is because the variable is not declared. Error Use of
uninitialized value... is because Perl uses a value of 'undef' where
variables are missing.
As an aside it is bad form to use meaningless variable names, and $a and
$b are special names that are used by core Perl so should be avoided.
Also it is prefereable to use lexical file handles and the
three-argument form of 'open', and incorporating the standard variable
$! into the die string will give valuable information about why the
operation failed.
Declaring your variables outside the 'while' loop would fix your
problem, but as you are interested only in the first line of the file it
is as well to remove the loop altogether. Take a look at the code below
and see if it meets your requirements.
HTH,
Rob
sub newValues {
my $file = shift;
open my $data, '', $file or die Unable to open data file: $!;
my $line = $data;
close $data;
my @data = split /~/, $line;
die Invalid data format if @data 3;
$data[0] += $previousarray[4];
$data[1] += $previousarray[7];
$data[2] += $previousarray[0];
open my $out, '', $file or die Unable to open output file: $!;
print $out join('~', @data[0,1,2]), \n;
close $out or die Failed to close output file: $!;
}
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line datafile, need data for another routine
Hi Chris!
On Friday 05 Feb 2010 11:56:49 Chris Coggins wrote:
I posted a question to this list yesterday from the google groups
interface, asking for help with the following. I have since tried to
post additional details in replies to that message using the google
groups site and none of my posts have shown up on the list so let's try
this again the right way.
I have a datafile with 1 line of data, 30 numbers delimited by tildes.
(Sample code below only uses 4 numbers to save time)
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
I neglected to mention in my original post that I need to access these
new values elsewhere in the script to perform additional math functions
with them.
I've tried several variations of the code below, including using arrays,
and none of them got through without the script failing. The new
datafile gets written, but it merely contains a ~. The errors I get are
use of uninitialized values in such and such line and variables needs
explicit package name. When the script does run, the variables lose
their values as soon as I close the file after inhaling it, making all
the rest of the actions in the subroutine futile.
the datafile used below initially contains 30 values that were written
previously, and this has been verified over and over.
Commenting on your code. Also, did you try using the Perl debugger (perl -d)
to debug the code?
sub newValues {
my($file) = shift;
1. Your code needs indentation.
2. Either do:
my $file = shift;
Or:
my ($file) = @_;
Otherwise, it is confusing and the meaning may be lost.
open(FILE, $file) or die(Unable to open data file.);
1. Don't use bareword filehandles - use lexicals.
2. Use three args open -
open my $fh, , $file or die...;
while (FILE) {
Better do while (my $line = FILE) instead of relying on $_.
my($a,$b,$c,$d) = split(/~/, $_);
Don't call your lexical variables $a and $b - they are special built in
variables. And you probably want an array here.
$a = $a+$previousarray[4]; # I've tried to perform this math action
after close(FILE) and get the same result - failure.
$b = $b+$previousarray[7];
$c = $c+$previousarray[0];
You are updating the values of $a, $b, and $c, but they:
1. Will disappear after the loop has exited.
2. Won't be available after the loop's exit.
}
close(FILE);
open(FILE, $file) || die (unable to open file);
Again, see my remarks about open.
print FILE ($a~$b~$c \n);
Are you using strict and warnings?
Regards,
Shlomi Fish
close(FILE);
}
#end sub
Now my datafile just contains a single tilde and no values. I've also
tried to bring the original data from the datafile into my(@array) and
get the same errors.
Keep in mind I need other subroutines to be able use these new values,
but these local variables lose their values once the file is closed.
I've also tried to declare them as global variables but I'm not doing
something right because the script won't execute.
I really need some help figuring this out if somebody would be kind
enough to help a novice.
--
-
Shlomi Fish http://www.shlomifish.org/
First stop for Perl beginners - http://perl-begin.org/
Deletionists delete Wikipedia articles that they consider lame.
Chuck Norris deletes deletionists whom he considers lame.
Please reply to list if it's a mailing list post - http://shlom.in/reply .
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line text file with numbers, need to add to them
For instance, here is your data file. data.txt
12~s1~s314~s5677~s899~s0~s
Then, here is the code.
#!/usr/bin/perl
open(DATA,data.txt);
while(DATA) {
$number=$_;
# print $number;
while ($number =~ /([0-9]+)~s/g){
printf (%d\n,$1);
}
}
close(DATA);
On Feb 4, 7:27 am, cacogg...@gmail.com (Chris) wrote:
I need some help with this problem.
I've got a text file datafile with 1 line of data comprised of 30
different numbers delimited with ~s.
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
I have tried for two days to figure out what I'm doing wrong, but I
keep getting needs a package name errors for every variable
nomenclature I try to work with. I've declare arrays and variables
until my fingers are numb and nothing is working. I'm using Perl 5.008
if that matters.
Can somebody please help?
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line text file with numbers, need to add to them
On Feb 4, 2:27 am, cacogg...@gmail.com (Chris) wrote: I need some help with this problem. I've got a text file datafile with 1 line of data comprised of 30 different numbers delimited with ~s. I need to open this file, grab this line of data, split it into individual numbers, perform some simple math (addition) on each number, and then put the new values back into the datafile, replacing the original data that was there. I have tried for two days to figure out what I'm doing wrong, but I keep getting needs a package name errors for every variable nomenclature I try to work with. I've declare arrays and variables until my fingers are numb and nothing is working. I'm using Perl 5.008 if that matters. Can somebody please help? I posted a reply this morning in response to several messages here, and I included two different versions of the script I'm using that keeps failing. I posted my reply through the google groups interface but my post does not show up at the google site and it's been about 8 hours since posting. How long does it take for posts to show up if one uses the google interface because this delay is absurd? -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: 1-line text file with numbers, need to add to them
On Feb 4, 4:35 pm, jwkr...@shaw.ca (John W. Krahn) wrote:
Chris wrote:
I need some help with this problem.
I've got a text file datafile with 1 line of data comprised of 30
different numbers delimited with ~s.
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
perl -i.bak -pe's/(\d+)/ $1 + 3 /eg' yourdatafile
John
--
The programmer is fighting against the two most
destructive forces in the universe: entropy and
human stupidity. -- Damian Conway
For instance, the below is your data file--- data.txt.
12~s1~s314~s5677~s899~s0~s
Here is the codes:
#!/usr/bin/perl
open(DATA,data.txt);
while(DATA) {
$number=$_;
# print $number;
while ($number =~ /([0-9]+)~s/g){
printf (%d\n,$1);
}
}
close(DATA);
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line text file with numbers, need to add to them
Frank wrote:
On Feb 4, 4:35 pm, jwkr...@shaw.ca (John W. Krahn) wrote:
Chris wrote:
I need some help with this problem.
I've got a text file datafile with 1 line of data comprised of 30
different numbers delimited with ~s.
I need to open this file, grab this line of data, split it into
individual numbers, perform some simple math (addition) on each
number, and then put the new values back into the datafile, replacing
the original data that was there.
perl -i.bak -pe's/(\d+)/ $1 + 3 /eg' yourdatafile
John
--
The programmer is fighting against the two most
destructive forces in the universe: entropy and
human stupidity. -- Damian Conway
Please don't quote sigs when you reply.
For instance, the below is your data file--- data.txt.
I'm sorry, I don't have a data file.
12~s1~s314~s5677~s899~s0~s
Here is the codes:
#!/usr/bin/perl
You should include the warnings and strict pragmas so that perl can help
you find mistakes:
use warnings;
use strict;
open(DATA,data.txt);
You should *always* verify that the file opened correctly before trying
to use a possibly invalid filehandle:
open FH, '', 'data.txt' or die Cannot open 'data.txt' $!;
while(DATA) {
$number=$_;
That is usually written as:
while ( my $number = FH ) {
But why are you calling a line of input text number?
# print $number;
while ($number =~ /([0-9]+)~s/g){
printf (%d\n,$1);
Why are you copying $1 to a string before having printf() convert it to
a string? Why use printf() when print() would be better and simpler:
print $1\n;
}
}
close(DATA);
John
--
The programmer is fighting against the two most
destructive forces in the universe: entropy and
human stupidity. -- Damian Conway
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line text file with numbers, need to add to them
F == Frank caichao1...@gmail.com writes:
F #!/usr/bin/perl
F open(DATA,data.txt);
F while(DATA) {
F $number=$_;
F # print $number;
F while ($number =~ /([0-9]+)~s/g){
F printf (%d\n,$1);
F }
F }
F close(DATA);
regardless of the poor code there and others have commented on it, why
did you post this three different times? and once using a different
address.
and please don't post code like that. it breaks many standard perl
coding rules, and it doesn't even do anything close to what the OP
wanted.
uri
--
Uri Guttman -- u...@stemsystems.com http://www.sysarch.com --
- Perl Code Review , Architecture, Development, Training, Support --
- Gourmet Hot Cocoa Mix http://bestfriendscocoa.com -
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 1-line text file with numbers, need to add to them
cc == chaccou...@camcontacts com chaccou...@camcontacts.net writes: cc Please unsubscribe from chaccou...@camcontacts.com and h...@camcontacts.com i don't manage this list. you can follow the directions for subscribing which are in the headers of each email on the list. uri -- Uri Guttman -- u...@stemsystems.com http://www.sysarch.com -- - Perl Code Review , Architecture, Development, Training, Support -- - Gourmet Hot Cocoa Mix http://bestfriendscocoa.com - -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
multiple onchange on 1 cgi file
hi all,
i'm newbie in perl.i have face problem how to add function ajax
(onchange) on my file.
this is my code...
$ajx_ctrl = $query-param('ajx_ctrl');
$co_id = $query - param('select_co');
my $exported_fx = sub {
my $searchterm = shift;
my $sql = qq select file_name from file_name where id_module = ? ;
my $dbh_label = $dbh_label;
my $sth = $dbh_label-prepare( $sql );
$sth-execute( $searchterm . '%' );
my $html1 = ;
$html1 = qq!select name=file_name id=id_module $input_style
#OnChange=details( ['users'],['ddiv'] ); return true;\n!;
my $firstrow = $sth-fetch();
if ( defined $firstrow ) {
$html1 .= qq!option ! .qq!- Select One -! . qq!/option\n!;
$html1.= qq!option! . $firstrow-[0] . qq!/option\n!;
# dot on each option from the db
while ( my $row = $sth-fetch() ) {
$html1.= qq!option! . $row-[0] . qq!/option\n!;
}
}
else
{$html1 .= qq!option ! .qq!- Select One -! . qq!/option\n!;}
# close off the select and return
$html1 .= qq!/select\n!;
#common_error($html1);
return($html1);
};
my $dbh_label = $dbh_label;
$file_base .=qq~ select name=file_name $input_style
option- Select One -/option
/select
~;
my $exported_form = sub {
my $searchterm2 = shift;
my $sql2 = qq select form_action from form where id_file = ? ;
my $dbh_label = $dbh_label;
my $sth2 = $dbh_label-prepare( $sql2 );
$sth2-execute( $searchterm2 . '%' );
my $html2 = ;
$html2 = qq!select name=form_action id=id_file $input_style
#OnChange=details( ['users'],['ddiv'] ); return true;\n!;
my $firstrow2 = $sth2-fetch();
if ( defined $firstrow2 ) {
$html2 .= qq!option ! .qq!- Select One -! . qq!/option\n!;
$html2.= qq!option! . $firstrow2-[0] . qq!/option\n!;
# dot on each option from the db
while ( my $row = $sth2-fetch() ) {
$html2.= qq!option! . $row-[0] . qq!/option\n!;
}
}
else
{$html2 .= qq!option ! .qq!- Select One -! . qq!/option\n!;}
# close off the select and return
$html2 .= qq!/select\n!;
return($html2);
};
my $dbh_label = $dbh_label;
$form_base .=qq~ select name=form_name $input_style
option- Select One -/option
/select
~;
#--- get module ---#
$sql = qq~
SELECT id, module
FROM module
~;
$sth = $dbh_label-prepare($sql);
$sth-execute() or common_error(SQL,Couldn't execute statement :
$DBI::errstr,1);
$sel_module .=qq~
option value=- Select One -/option
~;
while (($id, $module) = $sth-fetchrow_array())
{
$sel_module .=qq~
option value=$id $module/option
~;
}
$sth-finish();
#--#
### start add company form ##
my $Show_Form = sub {
my $html = ;
$html .= EOT;
HTML
HEADtitleCGI::Ajax Example/title
/HEAD
BODY
form action=setting_label_ajax.cgi method=post name=mainform
input type=hidden value=Save name=action
input type=hidden value=2 name=link
tr height=20
td bgcolor=$table_colordiv name=co_level id=co_level
$table_titlenbsp;b$forwhat/b/font/div/td
/tr
tr
td width=729
div align=left
!-- WE REPLACE THE HIDDEN TABLE ABOVE WITH THIS NEW ONE --
table width=100% border=1 cellpadding=0 cellspacing=0
style=border-collapse: collapse bordercolor=#11
id=AutoNumber21
tr
td
center
table border=0 cellpadding=1 cellspacing=2 style=border-
collapse: collapse bordercolor=#11 id=AutoNumber20
width=90%
tr height=8td/td/tr
tr height=25
td width=22%$content_styleModule/font/td
td width=2%$content_style:/font/td
td width=76% align=leftselect name=module id=module
OnChange=search( ['module','NO_CACHE'],['ddiv'] ); return true;
$input_style
$sel_module
/select
/td
/tr
tr height=25
td$content_styleFile Name/font/td
td$content_style:/font/td
td
div id=ddiv
select name=file id=file_name
OnChange=search2( ['file_name','NO_CACHE'],['ddiv'] ); return true;
$input_style
$file_base
/select
/div
/td
/tr
tr height=25
td$content_styleForm/font/td
td$content_style:/font/td
td
div id=ddiv
$form_base
/select
/div
/td
/tr
tr height=8td colspan=3/td/tr
/table
/td
/tr
/table
1-line text file with numbers, need to add to them
I need some help with this problem. I've got a text file datafile with 1 line of data comprised of 30 different numbers delimited with ~s. I need to open this file, grab this line of data, split it into individual numbers, perform some simple math (addition) on each number, and then put the new values back into the datafile, replacing the original data that was there. I have tried for two days to figure out what I'm doing wrong, but I keep getting needs a package name errors for every variable nomenclature I try to work with. I've declare arrays and variables until my fingers are numb and nothing is working. I'm using Perl 5.008 if that matters. Can somebody please help? -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: 1-line text file with numbers, need to add to them
Hi Chris! Have you visited http://perl-begin.org/ yet and read a good introductory book or tutorial? On Thursday 04 Feb 2010 09:27:32 Chris wrote: I need some help with this problem. I've got a text file datafile with 1 line of data comprised of 30 different numbers delimited with ~s. I need to open this file, grab this line of data, split it into individual numbers, perform some simple math (addition) on each number, and then put the new values back into the datafile, replacing the original data that was there. I have tried for two days to figure out what I'm doing wrong, but I keep getting needs a package name errors for every variable nomenclature I try to work with. I've declare arrays and variables until my fingers are numb and nothing is working. I'm using Perl 5.008 if that matters. You need to declare variables using my. Can you show us what you have so far? Regards, Shlomi Fish Can somebody please help? -- - Shlomi Fish http://www.shlomifish.org/ Why I Love Perl - http://shlom.in/joy-of-perl Deletionists delete Wikipedia articles that they consider lame. Chuck Norris deletes deletionists whom he considers lame. Please reply to list if it's a mailing list post - http://shlom.in/reply . -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: multiple onchange on 1 cgi file
On Thursday 04 Feb 2010 14:09:11 salmia wrote:
hi all,
i'm newbie in perl.i have face problem how to add function ajax
(onchange) on my file.
Hi salmia!
Have you visited http://perl-begin.org/ yet and read a good introductory book
or tutorial? Your code has many anti-patterns.
this is my code...
$ajx_ctrl = $query-param('ajx_ctrl');
$co_id= $query - param('select_co');
You should add use strict; and use warnings; at the top of your code, and
fix all relevant errors and warnings. Also, please don't use too terse
abbreviations like ajx instead of AJAX. I also think you should call
$ajax_ctrl $ajax_control_value.
my $exported_fx = sub {
Why are you declaring a subroutine like that as a closure assigned to a my
variable? A plain sub exported_fx { would be better.
my $searchterm = shift;
my $sql = qq select file_name from file_name where id_module = ? ;
my $dbh_label = $dbh_label;
What is the intention of the above line?
my $sth = $dbh_label-prepare( $sql );
$sth-execute( $searchterm . '%' );
Do you realise that doing «id_module = mysearch%» in the SQL won't actually
do a search? You need LIKE. And beware of SQL wildcards injection:
http://phroggy.com/weblog/63.html
Also it is customary to highlight the SQL keywords using ALL-CAPS.
my $html1 = ;
$html1 = qq!select name=file_name id=id_module $input_style
#OnChange=details( ['users'],['ddiv'] ); return true;\n!;
1. Use here-documents for multi-line strings:
http://www.shlomifish.org/lecture/Perl/Newbies/lecture4/string-
forms/here_doc.html
(short URL - http://xrl.us/bgukac ).
2. make sure $input_style does not have special HTML characters, or escape it.
my $firstrow = $sth-fetch();
if ( defined $firstrow ) {
$html1 .= qq!option ! .qq!- Select One -! . qq!/option\n!;
1. This should be one big string.
2. Please consider using a templating system such as:
http://template-toolkit.org/
$html1.= qq!option! . $firstrow-[0] . qq!/option\n!;
Now you have a potential cross-site scripting vulnerability here:
http://en.wikipedia.org/wiki/Cross-site_scripting
# dot on each option from the db
while ( my $row = $sth-fetch() ) {
$html1.= qq!option! . $row-[0] . qq!/option\n!;
}
}
else
{$html1 .= qq!option ! .qq!- Select One -! . qq!/option\n!;}
# close off the select and return
$html1 .= qq!/select\n!;
#common_error($html1);
Don't use ampersand-subroutine.
return($html1);
};
my $dbh_label = $dbh_label;
Again - why?
$file_base .=qq~ select name=file_name $input_style
option- Select One -/option
/select
~;
use here-docs.
my $exported_form = sub {
my $searchterm2 = shift;
my $sql2 = qq select form_action from form where id_file = ? ;
my $dbh_label = $dbh_label;
my $sth2 = $dbh_label-prepare( $sql2 );
$sth2-execute( $searchterm2 . '%' );
my $html2 = ;
$html2 = qq!select name=form_action id=id_file $input_style
#OnChange=details( ['users'],['ddiv'] ); return true;\n!;
my $firstrow2 = $sth2-fetch();
if ( defined $firstrow2 ) {
$html2 .= qq!option ! .qq!- Select One -! . qq!/option\n!;
$html2.= qq!option! . $firstrow2-[0] . qq!/option\n!;
# dot on each option from the db
while ( my $row = $sth2-fetch() ) {
Is there such a method of $sth called -fetch()? You should be more explicit -
fetchrow_arrayref , etc.
$html2.= qq!option! . $row-[0] . qq!/option\n!;
}
}
else
{$html2 .= qq!option ! .qq!- Select One -! . qq!/option\n!;}
# close off the select and return
$html2 .= qq!/select\n!;
return($html2);
};
This seems nearly identical to the previous function - please extract the
common functionality to a subroutine.
Regards
my $dbh_label = $dbh_label;
$form_base .=qq~ select name=form_name $input_style
option- Select One -/option
/select
~;
#--- get module ---#
$sql = qq~
SELECT id, module
FROM module
~;
$sth = $dbh_label-prepare($sql);
$sth-execute() or common_error(SQL,Couldn't execute statement :
$DBI::errstr,1);
$sel_module .=qq~
option value=- Select One -/option
~;
while (($id, $module) = $sth-fetchrow_array())
{
$sel_module .=qq~
option value=$id $module/option
~;
}
$sth-finish();
#--#
### start add company form ##
my $Show_Form = sub {
my $html = ;
Please use proper indentation inside of subroutines.
$html .= EOT;
Make sure here-docs are either «EOT» or «'EOT'» and not just EOT - see
Perl Best Practices.
Please fix all
Re: 1-line text file with numbers, need to add to them
Chris wrote: I need some help with this problem. I've got a text file datafile with 1 line of data comprised of 30 different numbers delimited with ~s. I need to open this file, grab this line of data, split it into individual numbers, perform some simple math (addition) on each number, and then put the new values back into the datafile, replacing the original data that was there. perl -i.bak -pe's/(\d+)/ $1 + 3 /eg' yourdatafile John -- The programmer is fighting against the two most destructive forces in the universe: entropy and human stupidity. -- Damian Conway -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Can't use string (1) as a HASH ref while strict refs in use at ./policy.sanitizer line 255.
Hi there,
I am trying to figure out why the following lines are giving me an error:
--- snip ---
$found{filter}{$filter}{family}{$family} = 1;
print keys %{ $found{filter}{$filter}{family} };
--- snip
here's the error
Can't use string (1) as a HASH ref while strict refs in use at
./policy.sanitizer line 255.
I am trying to the display all the keys for
$found{filter}{$filter}{family} please
Cheers,
Noah
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Can't use string (1) as a HASH ref while strict refs in use at ./policy.sanitizer line 255.
On 10/9/09 Fri Oct 9, 2009 2:12 PM, Noah noah-l...@enabled.com
scribbled:
Hi there,
I am trying to figure out why the following lines are giving me an error:
--- snip ---
$found{filter}{$filter}{family}{$family} = 1;
print keys %{ $found{filter}{$filter}{family} };
--- snip
here's the error
Can't use string (1) as a HASH ref while strict refs in use at
./policy.sanitizer line 255.
I am trying to the display all the keys for
$found{filter}{$filter}{family} please
One of the values in your nested hash has the value 1 rather than a
reference to a hash. Without seeing how you generated your hash it is
impossible to say which element is in error.
Use the Data::Dumper module to inspect nested hashes:
use Data::Dumper;
print Dumper(\%found);
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Can't use string (1) as a HASH ref while strict refs in use at ./policy.sanitizer line 255.
Noah wrote:
Hi there,
I am trying to figure out why the following lines are giving me an error:
--- snip ---
$found{filter}{$filter}{family}{$family} = 1;
print keys %{ $found{filter}{$filter}{family} };
--- snip
here's the error
Can't use string (1) as a HASH ref while strict refs in use at
./policy.sanitizer line 255.
I am trying to the display all the keys for
$found{filter}{$filter}{family} please
And which of those two lines in 255?
Apparently, $found{filter}{$filter}{family} == 1 so this line:
$found{filter}{$filter}{family}{$family} = 1; gives the error message.
--
Just my 0.0002 million dollars worth,
Shawn
Programming is as much about organization and communication
as it is about coding.
I like Perl; it's the only language where you can bless your
thingy.
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: $| = 1 ???
2009/9/11 Raymond Wan r@aist.go.jp: Perldoc is somewhat hard to get into...but it's the manual for a programming language, so that's expected; I don't think having pages to color and draw on would be a feasible idea for the next update. :-) I don't think you should tar every perldoc page with the same brush. Different pages have different purposes. Some pages are reference manual material -- so that you can look stuff up and quickly get information on particular features. Reference manuals are great for experts to get information on specific things -- regex metacharacters, special variables, etc -- but terrible for learning from. Some pages are tutorial material -- to introduce you to a concept gently, one idea at a time, and with examples. These are great to learn from, but not so good for finding specific information. Both types of page are necessary, and in perldoc I have found that both do their job well. The only difficulty I can imagine with perldoc is that there isn't a clear enough delineation between the two categories, so a beginner might find a reference manual when what they need is a tutorial or vice versa. And #4, perldoc and anything like perldoc is competing with things like Google. Some people want to find the Perldoc pages; others might rather find a blog or a newsgroup posting discussing the problem -- everyone learns differently. If you want specific information, such as the purpose of $|, nothing beats a reference manual. Anything else will waste your time. If you want to learn about a topic, then tutorials, newsgroup discussions, blogs etc are the way to go. Phil -- I have always wished for my computer to be as easy to use as my telephone; my wish has come true because I can no longer figure out how to use my telephone. --Bjarne Stroustrup -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
$| = 1 ???
Hi, i can not understand, what does this code: $| = 1; Thanks
Re: $| = 1 ???
2009/9/10 Tariq Doukkali tariq.doukk...@autoform.de: Hi, i can not understand, what does this code: $| = 1; $| is a special variable. All perl special variables are listed in perldoc perlvar. See that document for a full explanation. Phil -- I have always wished for my computer to be as easy to use as my telephone; my wish has come true because I can no longer figure out how to use my telephone. --Bjarne Stroustrup -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: $| = 1 ???
TD == Tariq Doukkali tariq.doukk...@autoform.de writes: TD Hi, TD i can not understand, what does this code: TD $| = 1; all of perl's special variables are documented in perldoc perlvar. read that first and see if you learn what $| does. if you still don't get it, then ask here for clarification. uri -- Uri Guttman -- u...@stemsystems.com http://www.sysarch.com -- - Perl Code Review , Architecture, Development, Training, Support -- - Gourmet Hot Cocoa Mix http://bestfriendscocoa.com - -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: $| = 1 ???
On Thursday 10 September 2009 11:17:33 Tariq Doukkali wrote: Hi, i can not understand, what does this code: $| = 1; $| is a special variable. Reading its description from perldoc perlvar: $| If set to nonzero, forces a flush right away and after every write or print on the currently selected output channel. Default is 0 (regardless of whether the channel is really buffered by the system or not; $| tells you only whether you've asked Perl explicitly to flush after each write). STDOUT will typically be line buffered if output is to the terminal and block buffered otherwise. Setting this variable is useful primarily when you are outputting to a pipe or socket, such as when you are running a Perl program under rsh and want to see the output as it's happening. This has no effect on input buffering. See getc in perlfunc for that. See select in perldoc on how to select the output channel. See also IO::Handle. (Mnemonic: when you want your pipes to be piping hot.) What it means is that after you do it, then print will output everything immediately, without buffering it beforehand. Hope it helps, Shlomi Fish Thanks -- - Shlomi Fish http://www.shlomifish.org/ Optimising Code for Speed - http://shlom.in/optimise Chuck Norris read the entire English Wikipedia in 24 hours. Twice. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: $| = 1 ???
2009/9/10 Philip Potter philip.g.pot...@gmail.com: 2009/9/10 Tariq Doukkali tariq.doukk...@autoform.de: Hi, i can not understand, what does this code: $| = 1; This means the programmer wishes that the buffer will be flushed after every write, or print. Normally (i.e. $| = 0), the computer stores output in a buffer, which is processed, flushed, after its full. Since this might cause messages to not appear at due time (suffering from buffering), you may want, or need, to set the autoflush special variable ($|) to true (in Perl, you assign a true value, 1 in this case, to it). $| is a special variable. All perl special variables are listed in perldoc perlvar. See that document for a full explanation. This isn't really helping, sorry. -- Erez The government forgets that George Orwell's 1984 was a warning, and not a blueprint http://www.nonviolent-conflict.org/ -- http://www.whyweprotest.org/ -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: $| = 1 ???
ES == Erez Schatz moonb...@gmail.com writes: $| is a special variable. All perl special variables are listed in perldoc perlvar. See that document for a full explanation. ES This isn't really helping, sorry. sorry, but pointing someone to the docs is helping more than directly answering the question. this has been debated for years and teaching newbies how to use the docs has always proven to be a win because it is a skill they need to learn. perl's docs are among the best out there and very comprehensive. uri -- Uri Guttman -- u...@stemsystems.com http://www.sysarch.com -- - Perl Code Review , Architecture, Development, Training, Support -- - Gourmet Hot Cocoa Mix http://bestfriendscocoa.com - -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: $| = 1 ???
2009/9/10 Erez Schatz moonb...@gmail.com: 2009/9/10 Philip Potter philip.g.pot...@gmail.com: 2009/9/10 Tariq Doukkali tariq.doukk...@autoform.de: Hi, i can not understand, what does this code: $| = 1; This means the programmer wishes that the buffer will be flushed after every write, or print. Normally (i.e. $| = 0), the computer stores output in a buffer, which is processed, flushed, after its full. Since this might cause messages to not appear at due time (suffering from buffering), you may want, or need, to set the autoflush special variable ($|) to true (in Perl, you assign a true value, 1 in this case, to it). $| is a special variable. All perl special variables are listed in perldoc perlvar. See that document for a full explanation. This isn't really helping, sorry. I'll let the OP say whether he was helped by my answer or not. I prefer not to give a direct answer on-list which I can easily get from the docs. I don't mind if others prefer to give a direct answer on-list. But to leave off the most important piece of knowledge the beginner could take away from this -- how he could have looked it up for himself -- is being most unhelpful. You have solved his problem for today, but you have not helped him grow as a programmer. What if tomorrow he needs to know what $; means? With my answer, he now knows he can consult perldoc perlvar -- with yours, he is none the wiser and must return here. Philip -- I have always wished for my computer to be as easy to use as my telephone; my wish has come true because I can no longer figure out how to use my telephone. --Bjarne Stroustrup -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: $| = 1 ???
On Thu, Sep 10, 2009 at 10:26, Bryan R Harris bryan_r_har...@raytheon.com wrote: ES == Erez Schatz moonb...@gmail.com writes: $| is a special variable. All perl special variables are listed in perldoc perlvar. See that document for a full explanation. ES This isn't really helping, sorry. sorry, but pointing someone to the docs is helping more than directly answering the question. this has been debated for years and teaching newbies how to use the docs has always proven to be a win because it is a skill they need to learn. perl's docs are among the best out there and very comprehensive. Curiously the most helpful people on this list seem to think the perldoc system is great, but I've always found it to be rather hard to use. If I need to figure out what $. means, how do I even start? I can't type perldoc '$.' (well, I can, but it doesn't find anything). How would I ever know that perlvar is the place to go without asking? Everybody gets pointed back to the perldoc system, and yet when they have more questions, they often still have to come back here to even start. You start by saying [perldoc perl][1] which gives you an index of what is in the docs. You then say to yourself Self, what is $., you answer Why, it is a variable, self, you then look at the index and see that there is a whole document on variables (Look self, there is a whole document named [perlvar][2] that the index says contains information about 'Perl predefined variables', maybe it is there?). I am not saying the Perl documentation is perfect (I wouldn't be working on [perlopref][3] if I thought that), but is usable. Many people just aren't aware it is there. 1. http://perldoc.perl.org/perl.html 2. http://perldoc.perl.org/perlvar.html 3. http://github.com/cowens/perlopref -- Chas. Owens wonkden.net The most important skill a programmer can have is the ability to read. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: 2 files, 1 package, shared constants
Stanisław T. Findeisen schrieb:
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Hello there
My application consists of several files. Some of them are to be run as
CGI scripts, the others from command line. There is also a common file
with constants and shared routines.
The question is: what is the most standard way to export constants from
that common file so that they could be used in the other files?
The Exporter.
package MyPackage;
use warnings;
use strict;
use constant {
~MY_FIRST_CONSTANT = 'hello world!'
};
*MY_SECOND_CONSTANT = [1, 3, 7];
*MY_SECOND_CONSTANT = \729;
sub routine1 {
~print Hello from routine1! $MyPackage::MY_SECOND_CONSTANT\n;
}
This is scary, what is with the typegobs there?
I would do something like this.
package MyPackage;
use warnings;
use strict;
use constant {
MY_FIRST_CONSTANT = 'hello world!'
};
use Exporter;
our @EXPORT = qw/MY_FIRST_CONSTANT
$MY_SECOND_CONSTANT
routine1
/;
#...@export_ok would be better
our $MY_SECOND_CONSTANT = [1, 3, 7];
sub routine1 {
print Hello from routine1! $MY_SECOND_CONSTANT\n;
}
== one.pl ==
use MyPackage;
routine1();
print MY_FIRST_CONSTANT;
print $MY_SECOND_CONSTANT;
see perldoc Exporter
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 2 files, 1 package, shared constants
Marc Lucksch wrote:
Stanisław T. Findeisen schrieb:
Subject: 2 files, 1 package, shared constants
Hello there
My application consists of several files. Some of them are to be run as
CGI scripts, the others from command line. There is also a common file
with constants and shared routines.
The question is: what is the most standard way to export constants from
that common file so that they could be used in the other files?
The Exporter.
That's probably true when you export symbols between packages.
snip
I would do something like this.
package MyPackage;
use warnings;
use strict;
use constant {
MY_FIRST_CONSTANT = 'hello world!'
};
use Exporter;
our @EXPORT = qw/MY_FIRST_CONSTANT
$MY_SECOND_CONSTANT
routine1
/;
#...@export_ok would be better
In this case there is only one package. Would you still bother with
Exporter? Why?
--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
2 files, 1 package, shared constants
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Hello there
My application consists of several files. Some of them are to be run as
CGI scripts, the others from command line. There is also a common file
with constants and shared routines.
The question is: what is the most standard way to export constants from
that common file so that they could be used in the other files?
Here is a minimal example:
- one.pl
package MyPackage;
use warnings;
use strict;
use constant {
~MY_FIRST_CONSTANT = 'hello world!'
};
*MY_SECOND_CONSTANT = [1, 3, 7];
*MY_SECOND_CONSTANT = \729;
sub routine1 {
~print Hello from routine1! $MyPackage::MY_SECOND_CONSTANT\n;
}
# This is to satisfy require()
1;
- two.pl
package MyPackage;
use warnings;
use strict;
require 'one.pl';
print 'The 1st constant is: ' . MyPackage-MY_FIRST_CONSTANT . \n;
print 'The 2nd constant is: ' . *MY_SECOND_CONSTANT . \n;
print ' SCALAR: ' . ${*MY_SECOND_CONSTANT{SCALAR}} . \n;
print ' ARRAY: ' . join(', ',
@{*MY_SECOND_CONSTANT{ARRAY}}) . \n;
MyPackage-routine1;
-
This produces output like this:
$ perl ./two.pl
The 1st constant is: hello world!
The 2nd constant is: *MyPackage::MY_SECOND_CONSTANT
~ SCALAR: 729
~ ARRAY: 1, 3, 7
Hello from routine1! 729
Funny thing is that in two.pl MyPackage-MY_FIRST_CONSTANT works, but
neither of these:
print '' . MY_FIRST_CONSTANT . \n;
print '' . MyPackage::MY_FIRST_CONSTANT . \n;
Bareword MY_FIRST_CONSTANT not allowed while strict subs in use at
./two.pl line ***.
Execution of ./two.pl aborted due to compilation errors.
So I suspect that although I managed to solve the problem, the solution
with MyPackage-MY_FIRST_CONSTANT is a bug in Perl or something?? Why
should I be able to call the constant subroutine, but not be able to
refer to the constant as is??
Why should I even bother with all these, since I am using only 1 package
MyPackage? The documentation says package is namespace is symbol table.
Why does MY_FIRST_CONSTANT work as is in one.pl, and not in two.pl?
I am using Perl v5.8.8.
STF
===
http://eisenbits.homelinux.net/~stf/ . My PGP key fingerprint is:
9D25 3D89 75F1 DF1D F434 25D7 E87F A1B9 B80F 8062
===
-BEGIN PGP SIGNATURE-
Version: GnuPG v1.4.7 (GNU/Linux)
Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org
iD8DBQFJpSAQ6H+hubgPgGIRAoYHAJ4uRiGGwlAbjB3whHx8nDOZCN58QwCdHZTA
Y7Anj2S1iXe93mES2d19REY=
=iwf7
-END PGP SIGNATURE-
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: 2 files, 1 package, shared constants
Stanisław T. Findeisen wrote: snip Funny thing is that in two.pl MyPackage-MY_FIRST_CONSTANT works, but neither of these: print '' . MY_FIRST_CONSTANT . \n; print '' . MyPackage::MY_FIRST_CONSTANT . \n; Concatenation seems like a bad idea. Try: print MY_FIRST_CONSTANT, \n; print MyPackage::MY_FIRST_CONSTANT, \n; (untested) -- Gunnar Hjalmarsson Email: http://www.gunnar.cc/cgi-bin/contact.pl -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: 2 files, 1 package, shared constants
Gunnar Hjalmarsson wrote: Concatenation seems like a bad idea. Try: print MY_FIRST_CONSTANT, \n; print MyPackage::MY_FIRST_CONSTANT, \n; Ee... you mean . instead of , right? This: print MY_FIRST_CONSTANT . \n; print MyPackage::MY_FIRST_CONSTANT . \n; yields this output: MY_FIRST_CONSTANT MyPackage::MY_FIRST_CONSTANT which I would say is even more strange (but I am new to Perl). STF === http://eisenbits.homelinux.net/~stf/ . My PGP key fingerprint is: 9D25 3D89 75F1 DF1D F434 25D7 E87F A1B9 B80F 8062 === signature.asc Description: OpenPGP digital signature
Re: 2 files, 1 package, shared constants
Stanisław T. Findeisen wrote: Gunnar Hjalmarsson wrote: Concatenation seems like a bad idea. Try: print MY_FIRST_CONSTANT, \n; print MyPackage::MY_FIRST_CONSTANT, \n; Ee... you mean . instead of , right? No, I mean ,. You can print() a list. -- Gunnar Hjalmarsson Email: http://www.gunnar.cc/cgi-bin/contact.pl -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: 2 files, 1 package, shared constants
Stanisław T. Findeisen wrote:
My application consists of several files. Some of them are to be run as
CGI scripts, the others from command line. There is also a common file
with constants and shared routines.
First: Please disregard my theory about concatenation. Concatenation is
ok, which is clearly stated in perldoc constant.
The question is: what is the most standard way to export constants from
that common file so that they could be used in the other files?
Since the files share the same package, no exporting is needed.
Here is a minimal example:
- one.pl
package MyPackage;
use warnings;
use strict;
use constant {
~MY_FIRST_CONSTANT = 'hello world!'
};
*MY_SECOND_CONSTANT = [1, 3, 7];
*MY_SECOND_CONSTANT = \729;
sub routine1 {
~print Hello from routine1! $MyPackage::MY_SECOND_CONSTANT\n;
}
# This is to satisfy require()
1;
- two.pl
package MyPackage;
use warnings;
use strict;
require 'one.pl';
print 'The 1st constant is: ' . MyPackage-MY_FIRST_CONSTANT . \n;
print 'The 2nd constant is: ' . *MY_SECOND_CONSTANT . \n;
print ' SCALAR: ' . ${*MY_SECOND_CONSTANT{SCALAR}} . \n;
print ' ARRAY: ' . join(', ',
@{*MY_SECOND_CONSTANT{ARRAY}}) . \n;
MyPackage-routine1;
I (now) believe that the problem is about compile time vs. runtime. When
two.pl is compiled, one.pl has not yet been required.
Two possible solutions:
1) Put the require statement in a BEGIN block.
BEGIN { require 'one.pl' }
2) Convert one.pl to a module (one.pm) and use() it.
use one;
--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
