[Bioperl-l] regular expression help!

[Madeleine Lemieux]

I'm not sure if this is the sort of thing you mean:

#!/usr/bin/perl -w

my @test_strings = ("acgttgcaacgt", "acgtacgt", "acgttgca", "ata");

foreach my $seq (@test_strings) {
     # force case change here, if necessary
     $seq =~ /([acgt]+)(?=([acgt]+)\1)/;
     my $fwd = $1;
     (my $rev = $2) =~ tr/acgt/tgca/;
     if ($fwd eq $rev) {
         print $seq, ' ', $fwd, ' ', $2, "\n";
     }
}

HTH,
Madeleine

> Hi, Everybody,
> I was trying to use a regex recognizing a patter of inverted repeat 
> DNA seq flanked by direct repeats (see below), it returns errors 
> saying "(?{...}) not terminated or {...} not balanced. Can anybody 
> help me sorting this out?
> The regex I have is:
> $regex =~ /\S+(\S+)(\S{10}).*(??{$rev=reverse(\2 =~ 
> tr/ATCG/TAGC/i);})\1.*/i;
> Thank you,
> Yang
>
>