Due to autovivification, you can half the number of lines in the snippet: 
my ($col1, $col2, $col3) = generate_data();
$hash{$col1}[0] += $col2;
$hash{$col1}[1] += $col3;

[download]
will do.

In reply to Re^2: Grouping By A Column by JavaFan
in thread Grouping By A Column by rocky13

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