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$/
CountZero
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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