Re^2: string replacement

in reply to Re: string replacement
in thread string replacement

my $pattern = join "|", map quotemeta, keys %replacements;

I think it would be good to also sort on length, as I discussed in Building Regex Alternations Dynamically. Although huck does make a good point that preserving the original ordering may be important too. Update after your reply: Good point about replacements within the replacements, whether the OP wants that or not and which method is more appropriate will depend on their requirements.

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Re^3: string replacement by Eily (Monsignor) on Sep 12, 2017 at 20:44 UTC
You're right about putting the longest strings first, if one searched string can be the start of another. That would be `my $pattern = join "\|", map quotemeta, sort {length $b <=> length $a} keys %replacements;`. With a single substitution operator you don't have to look for the presence of a searched string inside a replacement, because perl will only keep searching after the replaced item, so you can't replace part of a replacement.	[reply] [d/l]

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Re^3: string replacement
by Eily (Monsignor) on Sep 12, 2017 at 20:44 UTC

You're right about putting the longest strings first, if one searched string can be the start of another. That would be my $pattern = join "|", map quotemeta, sort {length $b <=> length $a} keys %replacements;.

With a single substitution operator you don't have to look for the presence of a searched string inside a replacement, because perl will only keep searching after the replaced item, so you can't replace part of a replacement.

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