Hi monks,

I've a contrived regex below that triggers "Use of uninitialised value in concatenation ..." warning. 

use strict;
use warnings;
use diagnostics;

my $str = "6%var% after";
# $str = "%var% after"; <-- warning is triggered

$str =~ s/(\d)?%var%(.*)/$1REPLACED$2/;

print "$str\n"

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When both $1 and $2 are initialised (i.e. $1 matched to the digit 6 and $2 to the word after, no warning is triggered. But with the 6 gone, $1 becomes uninitialised and so the "Use of uninitialised value in..." warning is triggered.

How do I fix that?

Thanks in anticipation :)

In reply to Regex triggering uninitialised values by kiat

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