Very useful regular expression quick reference

flags
  • g - global match
  • i - ignore case
  • m - match over multiple lines
Escaping
  • \ - special characters to literal and literal characters to special
Quantifiers
  • ? - matches zero or one times
  • * - matches zero or more times
  • + - matches one or more times
  • {n} - matches n times
  • {n, m} - matches at least n times, but not more than m times
Anchors
  • ^ - matches at the start of the line
  • $ - matches at the end of the line
  • \b - matches at the beginning or the end of a word
delimiter
  • (?:x) - matches x not remember the match
  • x(?=y) - matches x only if x is followed by y
  • x(?!y) - matches x only if x is not followed by y
Character Escapes
  • \s - matches whitespace
  • \S - matches anything but a whitespace
  • \f - matches a form-feed
  • \n - matches a linefeed
  • \r - matches a carriage return
  • \t - matches a horizontal tab
  • \v - matches vertical tab
  • \w - matches any alphanumeric character including the underscore. Equivalent to [A-Za-z0-9_]
  • \W - matches any non-word character. Equivalent to [^A-Za-z0-9_]
Others
  • . - matches any character except a newline

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