RECompendium

Somewhere on the web, there should be a compendium of useful (or near-useful) Perl Regular Expressions (also called patterns, regexes, and REs). Does it already exist? Until we can link to a more authoritative list from this page, let's put them here.

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Regexp::Common

The Regexp::Common module provides some commonly-needed patterns. See http://search.cpan.org/~abigail/Regexp-Common-2.113/

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The Patterns

Reader beware: Although we do our best to keep these accurate, the KwikiFormattingRules (and careless editing) may mangle some of these patterns. Use them at your own risk! (And help everybody out: Correct the bugs when you find them.)

These are somewhat modified from the perlfaq, section 4:

| <<NONDIGITS | has nondigits |

\D NONDIGITS

| <<WHOLE | a whole number |

^\d+$ WHOLE

| <<INT | an integer |

^-?\d+$ INT

| <<SIGNED | an integer which may or may not have a leading + sign |

^$l?\d+$ SIGNED

| <<REAL | real number |

^-?\d+.?\d*$ REAL

| <<DECIMAL | decimal (real) number |

/^-?(?:\d+(?:.\d*)?| .\d+)$/x DECIMAL

| <<FLOAT | C-style float |

/^($l?) (?=\d|.\d)\d*(.\d*)?

([Ee]([+-]?\d+))?$/x

FLOAT

| <<RBFLOAT | Root beer float |

\broot\s+beer\b &&

/\bice\s+cream\b/ &&
/\bstraw\b/

RBFLOAT

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US/Canada-style phone number with required area code and no "1" prefix:

/
   \(?     # optional parentheses
     \d{3} # area code required
   \)?     # optional parentheses
   [-\s.]? # separator is either a dash, a space, or a period.
     \d{3} # 3-digit prefix
   [-.]    # another separator
     \d{4} # 4-digit line number
/x

That pattern was shamelessly stolen from http://www.onlamp.com/pub/a/onlamp/2003/08/21/regexp.html

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Everything you could possibly need to know about Regexp and newlines http://ali.as/devel/newlines.html

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Use this to check for text that looks like an email address:

my $valid_email=1 if $email=~m|^[\w.\-]+\@[\w.\-]+\.\w{2,3}$|;

But beware! Some valid addresses don't match that pattern, through no fault of their owners. Send e-mail to Fred & Barney if you don't believe it:

Fred and Barney <"fred&barney"@redcat.com>

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Add more, please!