Did you write any own code for this?
use Data::Dumper;
my %hash;
while (<>) {
 chomp;
 my ($what,$where) = split /\s+/,$_;
 exists $hash{$what} || $hash{$what} = [];
 push @{$hash{$what}},$where;
}
print Dumper %hash;

[download]
(untested).
See perlreftut for more.
Sorry if my advice was wrong.

In reply to Re: Representing a connection matrix of graph by aitap
in thread Representing a connection matrix of graph by zing

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