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Matching unicode characters in a Ruby (1.9+) regexp

On Ruby 1.9+, standard ruby character classes like \w, \d will only match 7-Bit ASCII characters:

"foo" =~ /\w+/ # matches "foo" "füü" =~ /\w+/ # matches "f", ü is not 7-Bit ASCII

There is a collection of character classes that will match unicode characters. From the documentation:

  • /[[:alnum:]]/ Alphabetic and numeric character
  • /[[:alpha:]]/ Alphabetic character
  • /[[:blank:]]/ Space or tab
  • /[[:cntrl:]]/ Control character
  • /[[:digit:]]/ Digit
  • /[[:graph:]]/ Non-blank character (excludes spaces, control characters, and similar)
  • /[[:lower:]]/ Lowercase alphabetical character
  • /[[:print:]]/ Like [[:graph:]], but includes the space character
  • /[[:punct:]]/ Punctuation character
  • /[[:space:]]/ Whitespace character ([[:blank:]], newline, carriage return, etc.)
  • /[[:upper:]]/ Uppercase alphabetical
  • /[[:xdigit:]]/ Digit allowed in a hexadecimal number (i.e., 0-9a-fA-F)
  • /[[:word:]]/ A character in one of the following Unicode general categories Letter, Mark, Number, Connector_Punctuation
  • /[[:ascii:]]/ A character in the ASCII character set


"füü" =~ /[[:alpha:]]+/ # matches "füü" "‎१४" =~ /[[:digit:]]+/ # matches "१४"

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Author of this card:

Tobias Kraze
Last edit:
6 months ago
by Arne Hartherz
About this deck:
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Posted by Tobias Kraze to makandropedia