Useful Regular Expression Patterns

Phone Numbers:

• simple match that allows dashes as separators:
  ^\d{3}-\d{3}-\d{4}$
• allows periods, dashes or spaces as separators:
  ^(\(\d{3}\)|\d{3})[\s\.-]?\d{3}[\s\.-]?\d{4}$
• Matches to to the North American Numbering Plan (2009):
  ^(\([2-9][0-8]\d\)|[2-9][0-8]\d)[\s\.-]?[2-9]\d{2}[\s\.-]?\d{4}$

Postal Codes:

• simple match:
  ^([A-Z]\d[A-Z])\ {0,1}(\d[A-Z]\d)$
• allows unused “W” and “Z” as first characters:
  ^([ABCEGHJKLMNPRSTVWXYZ]\d[ABCEGHJKLMNPRSTVWXYZ])\ (\d[ABCEGHJKLMNPRSTVWXYZ]\d)$
• 2009 rules:
  ^[A-CEGHJ-NPR-TVXY]\d[A-CEGHJ-NPR-TV-Z][- /]?\d[A-CEGHJ-NPR-TV-Z]\d$

U.S. Zip Codes:

• Allows 5 and 5+4 zip codes:
  ^[0-9]{5}([- /]?[0-9]{4})?$

Roman Numerals:

• Unlike the ones I found all over the internet, this one actually works (up to 3999):
  ^(M{0,3})((D?C{0,3})|C[DM])((L?X{0,3})|X[LC])((V?I{0,3})|I[VX])$

Reading CSV:

• honours quoted strings:

  ^(?:([^",]+))?(?=,)|(?<=,)(?:[^",]*)?(?=[,$])|((?<=")[^"(\s*,)][^"]*(?="))|(?<=")(?=")|(?<=,)(?:[^,])*(?=$)

• Also see this post