@-

• @LAST_MATCH_START
• @-

  $-[0] is the offset of the start of the last successful match. $-[n] is the offset of the start of the substring matched by n-th subpattern, or undef if the subpattern did not match.

  Thus, after a match against $_, $& coincides with substr $_, $-[0], $+[0] - $-[0]. Similarly, $n coincides with substr $_, $-[n], $+[n] - $-[n] if $-[n] is defined, and $+ coincides with substr $_, $-[$#-], $+[$#-] - $-[$#-]. One can use $#- to find the last matched subgroup in the last successful match. Contrast with $#+, the number of subgroups in the regular expression. Compare with @+.

  This array holds the offsets of the beginnings of the last successful submatches in the currently active dynamic scope. $-[0] is the offset into the string of the beginning of the entire match. The nth element of this array holds the offset of the nth submatch, so $-[1] is the offset where $1 begins, $-[2] the offset where $2 begins, and so on.

  After a match against some variable $var:

  • $` is the same as substr($var, 0, $-[0])
  • $& is the same as substr($var, $-[0], $+[0] - $-[0])
  • $' is the same as substr($var, $+[0])
  • $1 is the same as substr($var, $-[1], $+[1] - $-[1])
  • $2 is the same as substr($var, $-[2], $+[2] - $-[2])
  • $3 is the same as substr($var, $-[3], $+[3] - $-[3])

  This variable was added in Perl 5.6.