if you capture something by () in regex and you get $1,$2,$3 and so on, why can't you just do
s/$2/something/
In this script, it's doing it but it's changing the value rather than position.
What i mean is,
[root@myserver tmp]# cat perl.test
#!/usr/bin/perl -w
use strict;
my $string = "123 123 345";
if ("$string" =~ /(\d+)\s+(\d+)\s+(\d+)/) {
$string =~ s/$2/something/;
print "$string\n";
}
[root@myserver tmp]# ./!$
./perl.test
something 123 345
I wanted this to change the value of position $2,
Therefore wanted to see
123 something 345
| [reply]
[d/l]
[select] |
That happens because your second capture, held in $2, is "123" so in your substitution inside the if $2 is interpolated to give s/123/something/, which runs quite happily and replaces the first occurence of "123" in $string. Had your string been "987 123 345" your code would have given the result you wanted but only as a side effect of your error. You could do it like this (not tested)
use strict;
use warnings;
my $string = q{123 123 345};
if ( $string =~
s{^(\d+\s+)(?:\d+)(\s+\d+)}{$1something$2} )
{
print qq{Succeeded\n$string\n};
}
else
{
print qq{Failed\n$string\n};
}
I hope this makes things a bit clearer.
Cheers, JohnGG | [reply]
[d/l]
[select] |