Re: split n characters into n chunks
Hi, you can use substr $myword, 1,3 function Thanks, Mahesh On Sun, Oct 25, 2009 at 3:13 PM, Michael Alipio daem0n...@yahoo.com wrote: Hi, How do I split a word into n subsets? my $word = thequickbrown If I want three subsets I should be able to create: the heq equ upto own Using split function with limit of 3 gives me: t h equickbrown Any idea how to do this? I'm thinking maybe I can just split the whole string and push each character into array, then loop through the array, getting 3 elements set in the proces.. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/ -- Thanks, MAhesh
Re: split n characters into n chunks
Shawn H Corey wrote:
Dr.Ruud wrote:
push @list, unpack x${_}a$size, $word for 0 .. $max;
Funnily enough, that is somehowwhat faster than
push @list, map unpack( x${_}a$size, $word ), 0 .. $max;
You don't need the push:
my @list = map unpack( x${_}a$size, $word ), 0 .. $max;
Yes, been there, and was also slower.
:)
--
Ruud
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Re: split n characters into n chunks
Shawn H Corey wrote:
John W. Krahn wrote:
$ perl -le'
my $word = thequickbrown;
my $subsets = 3;
print for $word =~ /(?=(.{$subsets}))/g;
Getting up there but substr is still the fastest.
I had to set the iterations to 300_000, to get rid of warnings.
$ perl5.8.8 3.pl
Rate arrays match unpack match3 match2 unpack2 substr
arrays 41265/s ---39%-40%-43%-44%-51%-73%
match67114/s 63% -- -2% -8% -9%-20%-56%
unpack 68337/s 66% 2% -- -6% -7%-19%-56%
match3 72816/s 76% 8% 7% -- -1%-13%-53%
match2 73350/s 78% 9% 7% 1% ---13%-52%
unpack2 84034/s104% 25% 23% 15% 15% ---45%
substr 153846/s273%129%125%111%110% 83% --
I moved some of the setup up, because I felt like it.
unpack2() has less overhead than unpack.
substr() mainly wins because it doesn't copy data.
(I assume it just creates an extra SvP on (a part of) it)
$ cat 3.pl
#!/usr/bin/perl -w
use strict;
$| = 1;
use Data::Dumper;
# Make Data::Dumper pretty
$Data::Dumper::Sortkeys = 1;
$Data::Dumper::Indent = 1;
# Set maximum depth for Data::Dumper, zero means unlimited
$Data::Dumper::Maxdepth = 0;
sub Testing() { 0 }
use Benchmark qw(:all);
my $word = thequickbrown;
my $size = 3;
Testing and print $_$/ for
my $re_match = sprintf( .(?=%s), . x ($size-1) ),
my $re_match2 = sprintf( (?=(%s)), . x $size ),
;
my $max = length( $word ) - $size;
if ( Testing ) {
via_arrays();
via_substr();
via_unpack();
via_match();
via_match2();
via_unpack2();
}
else {
cmpthese( 300_000, {
'arrays' = \via_arrays,
'substr' = \via_substr,
'unpack' = \via_unpack,
'unpack2' = \via_unpack2,
'match' = \via_match,
'match2' = \via_match2,
});
}
sub via_arrays {
my @list = ();
my @array = split //, $word;
push @list, join '', @array[ $_ .. $_ + $size - 1 ] for 0 .. $max;
print Dumper \...@list if Testing;
}
sub via_substr {
my @list = ();
push @list, substr( $word, $_, $size ) for 0 .. $max;
print Dumper \...@list if Testing;
}
sub via_unpack {
my @list = ();
push @list, (unpack( A${_}A$size, $word ))[1] for 0 .. $max;
print Dumper \...@list if Testing;
}
sub via_unpack2 {
my @list = ();
push @list, unpack( x${_}a$size, $word ) for 0 .. $max;
print Dumper \...@list if Testing;
}
sub via_match {
my @list = ();
push @list, substr( $word, $-[0], $size )
while $word =~ /$re_match/og;
print Dumper \...@list if Testing;
}
sub via_match2 {
my @list = ();
push @list, $_ for $word =~ /$re_match2/og;
print Dumper \...@list if Testing;
}
--
Ruud
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Re: split n characters into n chunks
Shawn H Corey wrote:
push @list, (unpack( A${i}A$size, $word ))[1];
Be careful with unpack A, because it rtrims.
Best use x to skip, and a to capture.
push @list, unpack x${_}a$size, $word for 0 .. $max;
Funnily enough, that is somehowwhat faster than
push @list, map unpack( x${_}a$size, $word ), 0 .. $max;
--
Ruud
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Re: split n characters into n chunks
Dr.Ruud wrote:
Shawn H Corey wrote:
push @list, (unpack( A${i}A$size, $word ))[1];
Be careful with unpack A, because it rtrims.
Best use x to skip, and a to capture.
push @list, unpack x${_}a$size, $word for 0 .. $max;
Funnily enough, that is somehowwhat faster than
push @list, map unpack( x${_}a$size, $word ), 0 .. $max;
You don't need the push:
my @list = map unpack( x${_}a$size, $word ), 0 .. $max;
--
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.
--
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split n characters into n chunks
Hi, How do I split a word into n subsets? my $word = thequickbrown If I want three subsets I should be able to create: the heq equ upto own Using split function with limit of 3 gives me: t h equickbrown Any idea how to do this? I'm thinking maybe I can just split the whole string and push each character into array, then loop through the array, getting 3 elements set in the proces.. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: split n characters into n chunks
Michael Alipio wrote: Any idea how to do this? I'm thinking maybe I can just split the whole string and push each character into array, then loop through the array, getting 3 elements set in the proces.. Split the string into an array, loop through it and use a slice to join the elements. -- 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: split n characters into n chunks
On Sunday 25 Oct 2009 14:39:32 Shawn H Corey wrote: Michael Alipio wrote: Any idea how to do this? I'm thinking maybe I can just split the whole string and push each character into array, then loop through the array, getting 3 elements set in the proces.. Split the string into an array, loop through it and use a slice to join the elements. Why not use perldoc -f substr ( http://perldoc.perl.org/functions/substr.html ) in a loop? Alternatively one can use unpack but I'm not sure how well it would handle Unicode characters. Regards, Shlomi Fish -- - Shlomi Fish http://www.shlomifish.org/ First stop for Perl beginners - http://perl-begin.org/ 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: split n characters into n chunks
Shlomi Fish wrote:
Why not use perldoc -f substr ( http://perldoc.perl.org/functions/substr.html
) in a loop? Alternatively one can use unpack but I'm not sure how well it
would handle Unicode characters.
You're right, substr works best.
#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;
# Make Data::Dumper pretty
$Data::Dumper::Sortkeys = 1;
$Data::Dumper::Indent = 1;
# Set maximum depth for Data::Dumper, zero means unlimited
$Data::Dumper::Maxdepth = 0;
use Benchmark qw(:all);
my $word = thequickbrown;
my $size = 3;
cmpthese( 50_000, {
'via_arrays' = \via_arrays,
'via_substr' = \via_substr,
'via_unpack' = \via_unpack,
});
# for testing only
# via_arrays();
# via_substr();
# via_unpack();
sub via_arrays {
my @array = split //, $word;
my $max = @array - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, join '', @array[ $i .. $i+$size-1 ];
}
# print Dumper \...@list; #for testing only
}
sub via_substr {
my $max = length( $word ) - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, substr( $word, $i, $size );
}
# print Dumper \...@list; #for testing only
}
sub via_unpack {
my $max = length( $word ) - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, (unpack( A${i}A$size, $word ))[1];
}
# print Dumper \...@list; #for testing only
}
--
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.
--
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http://learn.perl.org/
Re: split n characters into n chunks
Michael Alipio wrote: my $word = thequickbrown If I want three subsets I should be able to create: the heq equ . upto . own print substr( $word, $-[0], 3 ) while $word =~ /.(?=..)/g; -- Ruud -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: split n characters into n chunks
Dr.Ruud wrote:
print substr( $word, $-[0], 3 )
while $word =~ /.(?=..)/g;
Doesn't beat substr.
#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;
# Make Data::Dumper pretty
$Data::Dumper::Sortkeys = 1;
$Data::Dumper::Indent = 1;
# Set maximum depth for Data::Dumper, zero means unlimited
$Data::Dumper::Maxdepth = 0;
use Benchmark qw(:all);
my $word = thequickbrown;
my $size = 3;
cmpthese( 50_000, {
'via arrays' = \via_arrays,
'via substr' = \via_substr,
'via unpack' = \via_unpack,
'via match' = \via_match,
});
# for testing only
# via_arrays();
# via_substr();
# via_unpack();
# via_match();
sub via_arrays {
my @array = split //, $word;
my $max = @array - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, join '', @array[ $i .. $i+$size-1 ];
}
# print Dumper \...@list; #for testing only
}
sub via_substr {
my $max = length( $word ) - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, substr( $word, $i, $size );
}
# print Dumper \...@list; #for testing only
}
sub via_unpack {
my $max = length( $word ) - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, (unpack( A${i}A$size, $word ))[1];
}
# print Dumper \...@list; #for testing only
}
sub via_match {
my @list = ();
push @list, substr( $word, $-[0], 3 )
while $word =~ /.(?=..)/g;
#print Dumper \...@list; #for testing only
}
--
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: split n characters into n chunks
Michael Alipio wrote:
Hi,
Hello,
How do I split a word into n subsets?
my $word = thequickbrown
If I want three subsets I should be able to create:
the
heq
equ
upto
own
$ perl -le'
my $word = thequickbrown;
my $subsets = 3;
print for $word =~ /(?=(.{$subsets}))/g;
'
the
heq
equ
qui
uic
ick
ckb
kbr
bro
row
own
John
--
The programmer is fighting against the two most
destructive forces in the universe: entropy and
human stupidity. -- Damian Conway
--
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For additional commands, e-mail: beginners-h...@perl.org
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Re: split n characters into n chunks
John W. Krahn wrote:
$ perl -le'
my $word = thequickbrown;
my $subsets = 3;
print for $word =~ /(?=(.{$subsets}))/g;
Getting up there but substr is still the fastest.
#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;
# Make Data::Dumper pretty
$Data::Dumper::Sortkeys = 1;
$Data::Dumper::Indent = 1;
# Set maximum depth for Data::Dumper, zero means unlimited
$Data::Dumper::Maxdepth = 0;
my $Testing = $ARGV[0] || 0;
use Benchmark qw(:all);
my $word = thequickbrown;
my $size = 3;
if( $Testing ){
via_arrays();
via_substr();
via_unpack();
via_match();
via_match2();
}else{
cmpthese( 50_000, {
'via arrays' = \via_arrays,
'via substr' = \via_substr,
'via unpack' = \via_unpack,
'via match' = \via_match,
'via match2' = \via_match2,
});
}
sub via_arrays {
my @array = split //, $word;
my $max = @array - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, join '', @array[ $i .. $i+$size-1 ];
}
# print Dumper \...@list; #for testing only
}
sub via_substr {
my $max = length( $word ) - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, substr( $word, $i, $size );
}
# print Dumper \...@list; #for testing only
}
sub via_unpack {
my $max = length( $word ) - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, (unpack( A${i}A$size, $word ))[1];
}
# print Dumper \...@list; #for testing only
}
sub via_match {
my @list = ();
push @list, substr( $word, $-[0], 3 )
while $word =~ /.(?=..)/g;
# print Dumper \...@list; #for testing only
}
sub via_match2 {
my @list = ();
push @list, $_ for $word =~ /(?=(.{$size}))/g;
# print Dumper \...@list; #for testing only
}
--
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: split n characters into n chunks
Shawn H Corey wrote:
John W. Krahn wrote:
$ perl -le'
my $word = thequickbrown;
my $subsets = 3;
print for $word =~ /(?=(.{$subsets}))/g;
Getting up there but substr is still the fastest.
#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;
# Make Data::Dumper pretty
$Data::Dumper::Sortkeys = 1;
$Data::Dumper::Indent = 1;
# Set maximum depth for Data::Dumper, zero means unlimited
$Data::Dumper::Maxdepth = 0;
my $Testing = $ARGV[0] || 0;
use Benchmark qw(:all);
my $word = thequickbrown;
my $size = 3;
if( $Testing ){
via_arrays();
via_substr();
via_unpack();
via_match();
via_match2();
}else{
cmpthese( 50_000, {
'via arrays' = \via_arrays,
'via substr' = \via_substr,
'via unpack' = \via_unpack,
'via match' = \via_match,
'via match2' = \via_match2,
});
}
sub via_arrays {
my @array = split //, $word;
my $max = @array - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, join '', @array[ $i .. $i+$size-1 ];
}
# print Dumper \...@list; #for testing only
}
sub via_substr {
my $max = length( $word ) - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, substr( $word, $i, $size );
}
# print Dumper \...@list; #for testing only
}
sub via_unpack {
my $max = length( $word ) - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, (unpack( A${i}A$size, $word ))[1];
}
# print Dumper \...@list; #for testing only
}
sub via_match {
my @list = ();
push @list, substr( $word, $-[0], 3 )
while $word =~ /.(?=..)/g;
# print Dumper \...@list; #for testing only
}
sub via_match2 {
my @list = ();
push @list, $_ for $word =~ /(?=(.{$size}))/g;
Why the for loop?
my @list = $word =~ /(?=(.{$size}))/g;
# print Dumper \...@list; #for testing only
}
John
--
The programmer is fighting against the two most
destructive forces in the universe: entropy and
human stupidity. -- Damian Conway
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http://learn.perl.org/
Re: split n characters into n chunks
John W. Krahn wrote:
Why the for loop?
my @list = $word =~ /(?=(.{$size}))/g;
# print Dumper \...@list; #for testing only
}
Because you sent it with a loop. It also seems faster.
#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;
# Make Data::Dumper pretty
$Data::Dumper::Sortkeys = 1;
$Data::Dumper::Indent = 1;
# Set maximum depth for Data::Dumper, zero means unlimited
$Data::Dumper::Maxdepth = 0;
my $Testing = $ARGV[0] || 0;
use Benchmark qw(:all);
my $word = thequickbrown;
my $size = 3;
if( $Testing ){
via_arrays();
via_substr();
via_unpack();
via_match();
via_match2();
via_match3();
}else{
cmpthese( 50_000, {
'via arrays' = \via_arrays,
'via substr' = \via_substr,
'via unpack' = \via_unpack,
'via match' = \via_match,
'via match2' = \via_match2,
'via match3' = \via_match3,
});
}
sub via_arrays {
my @array = split //, $word;
my $max = @array - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, join '', @array[ $i .. $i+$size-1 ];
}
# print Dumper \...@list; #for testing only
}
sub via_substr {
my $max = length( $word ) - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, substr( $word, $i, $size );
}
# print Dumper \...@list; #for testing only
}
sub via_unpack {
my $max = length( $word ) - $size;
my @list = ();
for my $i ( 0 .. $max ){
push @list, (unpack( A${i}A$size, $word ))[1];
}
# print Dumper \...@list; #for testing only
}
sub via_match {
my @list = ();
push @list, substr( $word, $-[0], 3 )
while $word =~ /.(?=..)/g;
# print Dumper \...@list; #for testing only
}
sub via_match2 {
my @list = ();
push @list, $_ for $word =~ /(?=(.{$size}))/g;
# print Dumper \...@list; #for testing only
}
sub via_match3 {
my @list = $word =~ /(?=(.{$size}))/g;
# print Dumper \...@list; #for testing only
}
--
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/
