On Thu, 2004-05-27 at 11:21, Ramprasad A Padmanabhan wrote:
> On Thu, 2004-05-27 at 15:09, Jose Alves de Castro wrote:
> That was simply neat. I had read in a perl book ' there is always a
> shorter way in perl '. I think this proves it.
>
> But to think of it there is one hitch
>
> suppose my string is 'god'
>
> Assume
> $word = "good"
> $r = qr/^[god]+$/
>
>
> then $r would match $word. Can you think of a good work around ?
Oh... you want one of each letter only, is that it? Oh boy...
perl -lne 'BEGIN{for(qw(g o d)){$r{$_}++}}split/
/;for(@_){%a=%r;$a{$_}-- for split//;print unless grep $a{$_},keys %a}'
file
As before, I'm gonna tear this down :-)
=====================
#!/usr/bin/perl -lne
use strict;
BEGIN { for (qw(g o d)) { $r{$_}++} }
split/ /;
for (@_) {
%a=%r;
$a{$_}-- for split//;
print unless grep $a{$_},keys %a
}
=====================
Now I'm going to explain it (or at least try to...)
=====================
#!/usr/bin/perl -lne
# the -l switch chomps the line for you, and when you print, it prints
the \n too (for a better understanding of this, perldoc perlrun and then
search for -l)
use strict;
# I don't use this for one-liners, but always use it for scripts
my %r;
BEGIN { for (qw(g o d)) { $r{$_}++} }
# ok, our BEGIN block now holds how many of each letter we want
split/ /;
# we split the input line in words
my %a
for (@_) { # for each word
%a = %r; # we note how many of each letter we want
$a{$_}-- for split//; # and for each letter we have, we note down that
there's one less of that letter we need
print unless grep $a{$_},keys %a
# if there is any element in the hash %a with a number different from
0, we don't print it
}
=====================
I hope this is what you wanted :-)
Since this is a beginners list, I'm going to explain this line a bit
further:
$a{$_}-- for split//;
This is the same as:
for (split //) { $a{$_}-- }
Which is the same as:
for (split //, $_) { $a{$_}-- }
Basically, we split the word with an empty regular expression (meaning
we'll get its characters) and for each of those characters we decrement
its corresponding value in %a (even if it doesn't exist, for that
matter).
HTH, :-)
jac
> Thanks
> Ram
>
--
Josà Alves de Castro <[EMAIL PROTECTED]>
Telbit - Tecnologias de InformaÃÃo
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
<http://learn.perl.org/> <http://learn.perl.org/first-response>
