From: Robert Dober <robert.dober@...>
Date: 2011-03-22T23:13:35+09:00
Subject: Re: summing values in a hash?

On Tue, Mar 22, 2011 at 2:05 PM, Robert Klemme
<shortcutter@googlemail.com> wrote:
> On Tue, Mar 22, 2011 at 2:01 PM, Adam Prescott <mentionuse@gmail.com> wrote:
>> On Tue, Mar 22, 2011 at 12:57 PM, Jen <jen.bottom@gmail.com> wrote:
>>
>>> Is there an inbuilt method to sum all values in a hash and return the
>>> result?
>>>
>>> I.E something like puts hash[values].sum
>>>
>>
>> You could try
>>
>> hash.values.inject { |a, b| a + b }
>>
>> Alternatively, you have the shorter form, inject(&:+) or inject(:+)
>> depending on your version of Ruby. 1.8.7 and higher should support all
>> three.
>
> You should rather use a different idiom because your solution breaks
> for empty Hash:
>
> irb(main):001:0> {}.values.inject {|a,b|a+b}
> => nil
> irb(main):002:0> {}.values.inject(0) {|a,b|a+b}
> => 0
slightly better, because working ;)
    .inject(0){|a,(_,b)|a+b}
Cheers
R.