Sum values in 5th column that correspond to same field in 2nd column

Question

Considering below file:

0,2,,,10
0,2,,,15
0,1,,,984
0,2,,,9
1,14,,,5

Using awk, I need to calculate the total value in $5 per each $2.

The desired output would look like below:

2,34
1,984
14,5

Answer 1

Try:

awk -F, '{a[$2]+=$5};END{for(i in a)print i","a[i]}' <file

A note that array traversal in POSIX awk is unspecified order.

Answer 2

With gnu datamash:

datamash -t ',' -s -g 2 sum 5 <infile

the output will be sorted by 2nd column:

1,984
14,5
2,34

Answer 3

I'd be tempted to use perl:

#!/usr/bin/env perl
use strict;
use warnings;

my %things;

while (<>) {
    my ( undef, $key, @rest ) = split(/,/);
    $things{$key} += pop(@rest);
}

foreach my $key ( sort { $a <=> $b } keys %things ) {
    print "$key = $things{$key}\n";
}

You could condense that down to a one liner if needs be.