Anyone developed a clean solution for this? Any advice would be appreciated.

If you use some SQL server, use its capabilities to do the work for you. I know MySQL can use: 

SELECT foo, SUM(bar) FROM xyzzy GROUP BY foo

[download]
If you're not using SQL, or your SQL doesn't have this functionality, I'd sum first, and iterate later: 
my @data = (
    [ 'a', 1 ],
    [ 'a', 2 ],
    [ 'b', 3 ],
    [ 'b', 4 ]
);
my %totals;
my @order;
for (@data) {
    push @order, $_->[0] unless exists $totals{$_->[0]};
    $totals{$_->[0]} += $_->[1];
}
for (@order) {
    # Do something with $totals{$_}
}

[download]
If order is not important, leave out all @order stuff, and iterate over keys %totals; 

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In reply to Re: How to loop over groups by Juerd
in thread How to loop over groups by eisenstein

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