Ruby Programming/Reference/Objects/Regexp

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Class Regexp holds a regular expression, used to match a pattern of strings. Regular expressions can be created using /../ or by using the constructor "new".

[edit] CONSTANTS

1. EXTENDED : Ignore spaces and newlines in regexp.
2. IGNORECASE : Matches are case insensitive.
3. MULTILINE : Newlines treated as any other character.

[edit] CLASS METHODS

• compile : Regexp.compile( pattern [, options [ lang ] ] ) -> aRegexp

•     This method is a synonym for method "new". 
  

• escape : Regexp.escape( aString ) -> aNewString

•    Escapes any characters that have special meaning in a regular expression. 
     For example : 
     Regexp.escape('\\*?{}.')  » \\\\\*\?\{\}\. 
  

• last_match : Regexp.last_match -> aMatchData

•     Returns the MatchData object generated by the last successful pattern match. 
      Equivalent to reading the global variable $~. 
  

• new : Regexp.new( pattern [, options [ lang ] ] ) -> aRegexp

•     Constructs a regular expression from the pattern. The pattern can be either a string or 
      a "regexp".
      For example: 
      Regexp.new("xyz") » /xyz/
  

• quote : Regexp.quote( aString ) -> aNewString

•     A synonym for escape method.
  

[edit] INSTANCE METHODS

• == : rxp == aRegexp -> true or false

•     Two regular expressions are equal if their patterns match and they have same character
      set code and theie casefold? values are same.
  

• === : rxp === aString -> true or false

•     Synonym for Regexp#=~ used in case statements
  

• =~ : rxp === aString -> true or false

•     Matches a regular expression with string and returns the offset of the start of match or nil
      if a match fails. 
  

• ~ : ~ rxp -> anInteger or nil

•     Match---Matches rxp against the contents of $_. Equivalent to rxp =~ $_. 
      For example:
      $_ = "input data"  
      ~ /at/  » 7  
  

• casefold? : rxp.casefold? Returns true or false.

•     Returns the value of case-insensitive flag.
  

• kcode : rxp.kcode -> aString

•     Returns character set code for the regexp.
  

• match : rxp.match(aString) -> aMatchData or nil

•     Returns a MatchData object or nil if match is not found.
  

• source : rxp.source -> aString

•     Returns the original string of the pattern.
      For example : /xyz/.source >> xyz