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

Hi Monks!
I would like to have a total sum of the values from this array of hashes, any suggestions?
...
print Dumper \@pe_total;

$VAR1 = [
{
'COMP_TOTAL' => '2445.00'
},
{
'COMP_TOTAL' => '728.00'
}
];
...

[download]

Thanks for help!

Replies are listed 'Best First'.
Re: Sum of values in an array
by toolic (Bishop) on Sep 25, 2014 at 19:40 UTC
    One way: 
    use warnings;
use strict;
use List::Util qw(sum);

my @pe_total = (
    {
    'COMP_TOTAL' => '2445.00'
    },
    {
    'COMP_TOTAL' => '728.00'
    }
);

print sum(map { $_->{COMP_TOTAL} } @pe_total), "\n";

__END__

3173

    [download]

    See also:

[reply]
[d/l]
      Would it be possible to be done without loading a Perl Module?
[reply]

        List::Util is in the Perl core. Try it out, you should already have it installed.

        Otherwise, BrowserUk has given you an alternative method.

[reply]
[reply]
Re: Sum of values in an array
by BrowserUk (Patriarch) on Sep 25, 2014 at 19:52 UTC

    Updated to address GrandFather's concern below. 

    my @pe_total = (
     {
     'COMP_TOTAL' => '2445.00'
     },
     {
     'COMP_TOTAL' => '728.00'
     }
 );;

my $total;
$total += $_->{COMP_TOTAL} for @pe_total; 
print $total;;
3173

    [download]
    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]

      I was surprised by my $total += $_->{COMP_TOTAL} for @pe_total; so I ran the code. No output generated so I modified the print to print "$^V >$total<"; which prints:

      v5.16.3 ><

      [download]

      What is different about the way you are running the sample code? Different Perl verion maybe?

      The B::Deparse of the summing line is:

      (my $total += $$_{'COMP_TOTAL'}) foreach (@pe_total);

      [download]

      but my Perl foo isn't strong enough to decide if that means $total is local to the loop body or not. The result implies that it is, at least for this version of Perl.

      Perl is the programming world's equivalent of English
[reply]
[d/l]
[select]

        You're right. I ran it in my REPL, thus globals; and added the my when posting (to encourage its use). Now corrected above. Thanks.

        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]

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