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Re: Regular expression for a comma separated string

by CountZero (Bishop)
on Nov 25, 2014 at 10:14 UTC ( #1108333=note: print w/replies, xml ) Need Help??

in reply to Regular expression for a comma separated string

Why not let Perl write the regex for you?
use Modern::Perl '2014'; use Algorithm::Permute; my @elements = qw/ A C T G /; my @permutations; Algorithm::Permute::permute { push @permutations, ( join '(?:', @eleme +nts ) . ')?)?)?'} @elements; my $regex = join '|', @permutations; $regex = qr/^(?:$regex)$/; say "Testing"; for my $length ( 1 .. 4 ) { my $p = new Algorithm::Permute( [ qw/ A C T G A C T G A C T G A C T G X +/, ' ' ], $length ); while ( my @res = $p->next ) { my $test = join( '', @res ); print "$test\t"; say $test=~ /$regex/ ? 'Accept' : 'Reject'; } }
Sample output:
Testing A Accept C Accept T Accept G Accept (...) X Reject Reject CA Accept AC Accept TC Accept CT Accept (...) GA Accept AA Reject CC Reject (...) AG Accept XC Reject CX Reject XT Reject (...) CTGA Accept TCGA Accept TGCA Accept TGAC Accept CAGA Reject ACGA Reject (...)
The final regex for your pattern will then be /^$regex\s*,\s*$regex$/


A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James

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