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Perl string replace: Match, but not replace, part of regex

Say I have a string in Perl I am trying to match and replace with stuff: 

$string =~ s/[^a-zA-Z]$find[^a-zA-Z]/$replace/g;

So as shown, I want to replace everything that is surrounded on both sides by nonletter characters. However, when I replace the string, I do NOT want to also replace these characters: they are just necessary for correct matching. How can I tell the Perl regex to avoid replacing the things surrounding $find?

Solution

  • Use perl lookaround assertions.

    s/(?<=[^a-zA-Z])$find(?=[^a-zA-Z])/$replace/g