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Commenting Perl regular expressions

Archive - Originally posted on "The Horse's Mouth" - 2005-09-30 08:49:12 - Graham Ellis

Do you sometimes find Perl regular expressions hard to follow? If you do, remember that you can use the "x" modifier which allows you to space them out; with the "x" modifier, white spaces in the regular expression are ignored.

You can go further; once you've specified the "x" modifier, you can embed comments in your regular expression - for example:



@cliad = ($log =~ /^    # line starts with

        .*              # any characters

        cliad           # then literally look for "cliad"

        .*              # then look for any characters

        $               # up to a line end

        /xmg);


See our regular expression course and resources to learn more about regular expressions.