Re: Unique keys for multiple values with a Hash

The idea is to push values into array references in the hash. You have a few other typos I have corrected. The following should run:

use strict;

my %hash = ();
my ($first, $second);
while (<DATA>)
{
    ($first, $second) = split;
    push (@{$hash{$first}}, $second); # from Perl Cookbook 5.7
}

while ((my $key, my $value) = each %hash) {
    print "the Key is: $key\n";
    print join("\n",@$value),"\n\n";
}

__END__
5       25
6       27
5       24
5       23
6       29      
6       30
4       22
5       25
6       27
4       22
4       21
[download]

Comment on Re: Unique keys for multiple values with a Hash Download Code

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Re: Re: Unique keys for multiple values with a Hash by Anonymous Monk on Jan 14, 2003 at 19:18 UTC
The problem that I'm having is that all the values are being put on the array of values, and I just need the unique values I.E. `the Key is: 4 22 21 the Key is: 5 25 24 23 the Key is: 6 27 29 30` [download]	[reply] [d/l]
Re: Re: Re: Unique keys for multiple values with a Hash by tall_man (Parson) on Jan 14, 2003 at 19:28 UTC
Sorry, I missed that the first time (as did some others). Here is a quick fix. Replace the final loop with this: `while ((my $key, my $value) = each %hash) { print "the Key is: $key\n"; my %seen = (); # Perl Cookbook 4.6 Extracting Unique Elements from a List my @uniq = grep { ! $seen{$_}++ } @$value; print join("\n",@uniq),"\n\n"; }` [download] Update: I see that Ovid also has a good one-pass solution.	[reply] [d/l]