An alternative using Mojo::Collection::Role::UtilsBy:
use Mojo::Collection 'c';
use Mojo::Util 'dumper';
my $start = c({name => 'name1', total => 2}, {name => 'name1', total => 3},
{name => 'name2', total => 7})->with_roles('+UtilsBy');
my $end = c(map { $_->reduce(sub { $a->{total} += $b->{total}; $a }) }
values %{$start->partition_by(sub { $_->{name} })});
print dumper $end->to_array;
-Dan
On Fri, Aug 3, 2018 at 11:27 AM Jason Cooper <[email protected]> wrote:
> You'd probably need to reduce it to a hash of name to total and then map
> that back to a Mojo::Collection, e.g.:
>
> #!/usr/bin/env perl
>
> use strict;
> use warnings;
>
> use Mojo::Collection;
> use Data::Dumper;
>
> my $collection= Mojo::Collection->new({name=>"name1", total=>2},
> {name=>"name1",total=>3}, {name=>"name2", total=>7});
>
>
> my $firstPass = $collection->reduce( sub {
> $a->{$b->{name}} += $b->{total};
>
> return $a;
> }, {});
>
> my $newCollection = Mojo::Collection->new(
> map {
> { name => $_, total => $firstPass->{$_} }
> } keys %{$firstPass}
> );
>
> print Dumper($collection);
> print Dumper($newCollection);
>
>
>
>
> On Friday, 3 August 2018 13:50:19 UTC+1, Stefan Adams wrote:
>>
>> I have a Mojo::Collection of hashes and I'd like to reduce the collection
>> similar to an SQL GROUP BY.
>>
>> Mojo::Collection->new({name=>"name1", total=>2},
>> {name=>"name1",total=>3}, {name=>"name2", total=>7})
>>
>>
>> This collection has three elements and the collection I'm looking for
>> would have two:
>>
>> {name=>"name1", total=>*5*}, {name=>"name2",total=>7}
>>
>>
>> I'm trying to group by name and then sum the totals within that group.
>>
>> It seems like I should use the reduce method of Mojo::Collection; if
>> that's appropriate, how could I accomplish that?
>>
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