Re: Problem about substitution..

[tom smith]

On Mon, Nov 2, 2009 at 7:41 PM, Remy Guo <rollingst...@gmail.com> wrote:

> hi folks,
> i've got problem when trying to perform a substitution.
>
> the text file i want to process is like this:
> ...
> XXXXXX  {
> ABDADADGA
> afj*DHFHH
> }  (a123)
> XXDFAAF {
> af2hwefh
> fauufui
> }  (b332)
> ...
>
> i want to match the content in the parenthesis (a123 and b332, here) and
> replace them with a sorted number (0;0,  0;1,  0;2,  .... 0; 255,  1;0,
> 1;1, ...1; 255, for example), so i wrote the script like this:
>     if (m/\}.*\(.*\)/)
>     {
>             $j++;
>             if ($j >= 255)
>             {
>                 $i++;
>                 $j = 0;
>             }
>
>             $_ =~ s/\(.*\)/$i;$j/
>      }
>
> now the problem is that, i'm sure the matching
> regex successfully matches the line that i want, but the subsitution just
> don't happen.  why?...
> need your help....thanks!
>
> - Remy
>


First, the s/// operator applies to $_ by default.

Second, as far as I can tell there's no indication anywhere in your script
as to what the value of $_ might be.

This works for me:

use strict;
use warnings;

open(my $INFILE, "<", "in.txt");
open(my $OUTFILE, ">", "out.txt");

my $line;
my $i = 0;
my $j = 0;

while ($line = <$INFILE>) {

    if ($line =~ /\((.*?)\)/) {

        $line =~ s/$1/$i;$j/;

        $j++;
        if ($j > 255) {
            $j = 0;
            $i++;
        }
    }

    print $OUTFILE $line;
}