addition in regular expressions

texuser74 has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks, I need to add a value while doing a find and replace i.e.

s!total of (.*?) and (.*?)\n!total is $1+$2\n!g;
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Please advise how to add $1 and $2, i am getting the string "$1+$2" instead of its total.

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Re: addition in regular expressions by ysth (Canon) on Dec 13, 2007 at 09:33 UTC
Or use one of the tricks to interpret an expression into a double-quoted string (which the right side of s/// is like): `s!total of (.?) and (.?)\n!total is @{[$1+$2]}\n!g` [download] -- CollegeGear.com - more than just college gear (though, yes, we have college-branded teddy bears)	[reply] [d/l]
Re^2: addition in regular expressions by texuser74 (Monk) on Dec 13, 2007 at 09:38 UTC
hi thanks, your solution did the magic for me.	[reply]
Re: addition in regular expressions by moritz (Cardinal) on Dec 13, 2007 at 09:25 UTC
Use the `/e`-Modifier: `s{total of (.?) and (.?)\n}{'total is ' . ($1+$2) . '\n!'}eg;` [download]	[reply] [d/l] [select]