Mastering Modern Perl: Writing Efficient and Maintainable Code/

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Greediness

Greediness

Learn how to apply greedy and nongreedy quantifiers of regex in Perl.

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Greedy quantifiers

The + and * quantifiers are greedy: they try to match the input string as much as possible. This can be particularly pernicious. Consider a naïve use of the “zero or more non-newline characters” pattern of .*:

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# a poor regex
my $hot_meal = qr/hot.*meal/;
say 'Found a hot meal!' if 'I have a hot meal' =~ $hot_meal;
say 'Found a hot meal!' if 'one-shot, piecemeal work!' =~ $hot_meal;

Greedy quantifiers start by matching everything at first. If that match doesn’t succeed, the regex engine will ...