Building Blocks
- \d a digit
- \D a non-digit
- \s a whitespace
- \S a non-whitespace
- \w a word
- \W a non-word
- \b a word boundary
- . any character
- \ Escape special char or start a sequence
Repeated Characters or Patterns
- ? 0 or 1 time
- + 0 or more times
- * 1 or more times
- {#} # of times
- {#,} # or more times
- {,#} 0 to # times
- {#, #} # to # of times
Specific Possible Characters
- [xyz] either x, y or z
- [^xyz] Any character besides x, y, or z
- [a-zA-Z] ranges of characters
Location of Characters
- ^ beginning of line
- $ end of line
- \A beginning of string
- \z end of string
Capturing
- (...) capture the pattern enclosed
- (...|...) capture either pattern enclosed
