You can still use a hash, but you have to check whether the key already exists before setting the value. 
#!/usr/bin/perl
use warnings;
use strict;

my %seen;
while (<DATA>) {
    my ($name, $count) = split;
    $seen{$name} = $count unless exists $seen{$name};

}
print "$_ $seen{$_}\n" for keys %seen;

__DATA__
nick 5
nick 10
nick 20
john 78
erik 9
erik 12

[download]

If you want to store the values in an array, use 

    push @keep, $_ unless $seen{$name}++;

[download]

Or, you can print the lines directly: 

    print unless $seen{$name}++;

[download]

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In reply to Re: How can I keep the first occurrence from duplicated strings? by choroba
in thread How can I keep the first occurrence from duplicated strings? by Anonymous Monk

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