hashes with multiple values per key

convenientstore has asked for the wisdom of the Perl Monks concerning the following question:

I have file below

12   AAAA
12   AAAA
15   BBBB
1222 CCCC
1    BBBB
[download]

and I am trying to run below so that I can gather everything
so that it would show

AAAA 24
BBBB 16
CCCC 1222
But below codes just do not add them together..

use strict;
my $value;
my $key;
my $sum = 0;
my %yahoo = ();

while (<>) {
    ($value,$key) = split;
#    print "$key, $value\n";
#    $sum += $value;
#    print "\$sum is $sum\n";
    push (@{$yahoo{$key}}, ($sum += $value));
}

foreach $key (sort keys %yahoo) {
       print "$key: @{$yahoo{$key}}\n";
}
[download]

Comment on hashes with multiple values per key Select or Download Code

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Re: hashes with multiple values per key by kyle (Abbot) on Aug 06, 2007 at 22:54 UTC
`use strict; use warnings; my %yahoo = (); while (<DATA>) { chomp; my ($value, $key) = split; $yahoo{$key} += $value; } foreach my $key (sort keys %yahoo) { print "$key: $yahoo{$key}\n"; } __DATA__ 12 AAAA 12 AAAA 15 BBBB 1222 CCCC 1 BBBB` [download] Output: `AAAA: 24 BBBB: 16 CCCC: 1222` [download]	[reply] [d/l] [select]
Re^2: hashes with multiple values per key by convenientstore (Pilgrim) on Aug 07, 2007 at 00:30 UTC
I didn't think below would work but it works `$yahoo{$key} += $value;` [download] isn't above same as `$yahoo{$key} = $yahoo{$key} + $value` [download] so first $yahoo{$key} would be null + $value and then next time it would come up with that value so that's why it works great!! thank you. Grandfather's solution , is bit advance for me, as I have not got to module part but I am reading that tonight and will try. thank you both !!!	[reply] [d/l] [select]
Re^3: hashes with multiple values per key by kyle (Abbot) on Aug 07, 2007 at 00:41 UTC
Yes, "`$yahoo{$key} += $value;`" is the same as "`$yahoo{$key} = $yahoo{$key} + $value;`". Look under "Assignment operators" in perlop.	[reply] [d/l] [select]
Re^4: hashes with multiple values per key by GrandFather (Saint) on Aug 07, 2007 at 01:10 UTC
Re: hashes with multiple values per key by GrandFather (Saint) on Aug 06, 2007 at 23:03 UTC
You could sum as you go, or you could sum afterwards: `use strict; use warnings; use List::Util; my %yahoo = (); while (<DATA>) { my ($value,$key) = split; push @{$yahoo{$key}}, $value; } foreach my $key (sort keys %yahoo) { my $sum = List::Util::sum (@{$yahoo{$key}}); print "$key: $sum\n"; } __DATA__ 12 AAAA 12 AAAA 15 BBBB 1222 CCCC 1 BBBB` [download] Prints: `AAAA: 24 BBBB: 16 CCCC: 1222` [download] DWIM is Perl's answer to Gödel	[reply] [d/l] [select]