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Re^3: Reading file and matching lines

by kcott (Abbot)
on Feb 14, 2014 at 00:33 UTC ( #1074918=note: print w/ replies, xml ) Need Help??


in reply to Re^2: Reading file and matching lines
in thread Reading file and matching lines

Firstly, you have no duplicates in any (of what you're calling) "scope". G123465798 is not a duplicate of G123456798: you've transposed the 5 and the 6. I've fixed this in the example below.

There's a standard idiom for checking for duplicates in this sort of scenario. Use a hash (often called %seen) that has as its keys whatever identifier you're checking. While processing, if the key exists, it's a duplicate, so skip/flag/etc. as appropriate; if the key doesn't exist, it's unique, so use it and then add it to the hash (usually done with a postfix increment).

Here's an example using your fixed data:

#!/usr/bin/env perl -l use strict; use warnings; my @data = ( [ qw{E123456789 G123456798 h12345} ], [ qw{E1234567 E7899874 G123456798 G123456789 G123456798 h1245} ], ); for my $scope (@data) { my %seen; for my $identifier (@$scope) { print $identifier unless $seen{$identifier}++; } }

Output:

E123456789 G123456798 h12345 E1234567 E7899874 G123456798 G123456789 h1245

-- Ken


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