Because that is how the pattern was written, each () corresponds to $n, so the first () is $1 the second is $2 and so on. Read http://perldoc.perl.org/perlintro.html#Parentheses-for-capturing, perlrequick and/or something from Tutorials

In reply to Re^3: Extract a pattern from a string by Anonymous Monk
in thread Extract a pattern from a string by avim1968

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