Regular Expressions Cheatsheet

Regular Expressions

. matches any character, except for line breaks

•     matches 0 or more of the preceding character
  

•     matched 1 or more of the preceding character
  

  ? preceding character is optional, matches 0 or 1 occurance
  \d matches any single digit
  \w matches any word character (字母，数字，下划线)
  [XYZ] matches any single character from the character class
  [XYZ]+ matches one or more any of the characters in the set
  $ matches the end of the string
  ^ matches the beginning of the string
  [^a-z] when inside of a character class, the ^ means NOT
  matched anything that is NOT a lowercase letter

w{3} three w
\D non-digit
\S non-whitespace
\W non-alphanumeric
\b matches the boundary between a word and a non-word character