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@files = qw(model4run1 model2run1 model4run2 model1run1); my $first = shift(@files); my $combined = $first; foreach (@files) { $combined &= $_; } $combined ^= $first; $combined =~ s/[^\x00].*//; my $prefix = substr($first, 0, length($combined)); print qq{Prefix is "$prefix"\n};
First I AND together all the elements of the array (therefore only bits that are the same for all items are set), then I XOR the result with the first element to get zeroes for all characters that are the same, then strip everything from the first nonzero character and last get as many characters from the first element as you have zeroes.

Update: You can of course replace the my $first = shift(@files); by my $first = $files[0];, the result will be the same and @files will be preserved.

Update: The code is wrong. It returns an incorrect result for

@files = qw(model4run1 model5run1);
See a fixed version here. It makes my solution a little slower, but it's still the fastest.

Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live.
   -- Rick Osborne

Edit by castaway: Closed small tag in signature

In reply to Re: Find common prefix from a list of strings by Jenda
in thread Find common prefix from a list of strings by Albannach

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