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Lazy matching helps correct problems with matching too much text and increases the matching efficiency.

With this regular expression we get the following output. With lazy matching, text is matched up to the first greater than, but because /g (globally) is used, it repeats until the string no longer has HTML. In our example above, the following text would be returned because everything between the first less than () is matched.Īdding a question mark after the asterisk makes the regular expression lazy and displays a better output.

For example, if you're parsing an HTML file and want to remove all HTML tags, the following greedy regular expression causes extra work and fails.īecause of the greedy matching, the regular expression matches the opening of the first tag and then matches everything to the end of the last tag. For example, if you're using a plus (+) instead of an asterisk, you could change it to "+?" in your regular expression.ĭoing a greedy match adds a lot of extra work that's usually not required, which makes matching text a lot slower. The question mark can be added to other regular expression tokens that are also greedy. Adding the question mark tells the computer to stop looking for matches once one match is found.

One method to make the regular expression not greedy ( lazy matching), is to add a question mark (?) after the asterisk (*), as shown below. This example returns "Matched: Computer Hope," not "Compute," because the text has multiple "e" characters. For example, the below Perl greedy regular expression ".*e" matches all text up to the last letter "e" in the $example variable. With regular expressions and wildcards, greedy describes a type of matching that continues looking for a match even after a match is found.