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Re: Regex help

by PetaMem (Priest)
on Dec 11, 2012 at 11:43 UTC ( #1008280=note: print w/ replies, xml ) Need Help??


in reply to Regex help

This is one of the easiest tasks for Perl. Contrary to the one-liner that would do, some more verbose code:

# let's define a sub that will return the matched id IF there was a ma +tch, undef else sub match_id { my $str = shift; if ($str =~ m{dp/(.\d+?)\z}) { # we assume our id is "some charact +er followed by digits" return "$1\n"; # will return id IF we had a match } return; # undefined if there was no match } # assume you have these strings one in a line - or not # and read the file to a list (one line = one list element) # then you can get a list of matches like so: my @ids = grep { defined $_ } map { match_id($_) } @lines_from_file;

If you have the strings scattered around your file, possibly several on one line, you better use the global modifier and a while loop. You also should tighten your regex then - specifying the ID more exact:

while ($file_content =~ m{dp/(.\d+?)}g) { # we have to omit the \z print "Found one: $1\n"; }

E.g. if you knew, all your Id's started with an upper-case letter and have always 8 digits, that would be

m{dp/([A-Z]\d{8})}g

Bye
 PetaMem
    All Perl:   MT, NLP, NLU


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