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Re: Find duplicate digits

by inman (Curate)
on Feb 15, 2006 at 15:35 UTC ( #530415=note: print w/replies, xml ) Need Help??

in reply to Find duplicate digits

Canonicalise the data and look for multiples. The grep tests for numbers where there are a number of multiples of which at least one is a pair. This solution works with numbers of any length and can be made to work with triples, quads etc. just by changing the grep test.

The OP didn't make it clear whether a number such as 0101 that has two pairs should be counted. You can always test the number of members of the list returned by the grep.

while (<DATA>){ print "$_" if grep {length $_ == 2} join('', sort split //, $_) =~ + /((\d)\2+)/g; } __DATA__ 0000 0001 0002 0003 0004 0005 0006 0007 0008 0009 0010 0011 0012 0013 0014 01511 451411
0011 0012 0013 0014 451411

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Re^2: Find duplicate digits
by Anonymous Monk on Feb 15, 2006 at 15:52 UTC
    Thanks, inman!

    Yes, I would like 1010 to be counted.

    I'm finding it hard to understand your grep. Where is the list that it's supposed to work on?

      The code is equivalent to
      while (<DATA>) { my $a = join('', sort split //, $_); my @a = $a =~ /((\d)\2+)/g; print "$_" if grep {length $_ == 2} @a; }

      holli, /regexed monk/
        Thanks, holli! That really helpful :)

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