Re: Regex triggering uninitialised values

Make the \d optional, not the capture:

use strict;
use warnings;

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

$str =~ s/(\d?)%var%(.*)/$1REPLACED$2/;  # <-- moved the '?'

print "$str\n"
[download]

By the way, I don't get the warning under Active Perl 5.6.1, but I did with perl v5.8.0 built for i386-freebsd

Comment on Re: Regex triggering uninitialised values Download Code

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Re^2: Regex triggering uninitialised values by kiat (Vicar) on Nov 19, 2004 at 17:49 UTC
Thanks, ikegami! How will the regex change if I need to match more than one digit before %var%? Just can't think of anything at the moment... Edited: Sorry, just discovered that moving the ? solves the problem. `#$str =~ s/(\d+?)%var%(.)/$1REPLACED$2/;</strikeout> As pointed out by Eimi Metamorphoumai $str =~ s/(\d)%var%(.*)/$1REPLACED$2/;</strikeout>` [download]	[reply] [d/l]
Re^3: Regex triggering uninitialised values by Eimi Metamorphoumai (Deacon) on Nov 19, 2004 at 18:01 UTC
Watch out! '`+?`' isn't the same as '``' in a regexp. If you want zero or more, you want '``'. '`+?`' will only match if there is one or more, but will match non-greedily (that is, as few characters as possible).	[reply] [d/l] [select]
Re^4: Regex triggering uninitialised values by kiat (Vicar) on Nov 19, 2004 at 18:06 UTC
Ah, thanks!	[reply]