• PCRE regex
  • Alternation

  • Alternation
  • Alternation


    Vertical bar characters are used to separate
    alternative patterns. For example, the pattern
    gilbert|sullivan matches either “gilbert” or “sullivan”.
    Any number of alternatives may appear, and an empty alternative is
    permitted (matching the empty string). The matching process tries
    each alternative in turn, from left to right, and the first one
    that succeeds is used. If the alternatives are within a subpattern
    (defined below), “succeeds” means matching the rest of the main
    pattern as well as the alternative in the subpattern.