From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2012-09-28T00:42:43+09:00
Subject: Re: subtract values of a array

On Thu, Sep 27, 2012 at 5:36 PM, Roelof Wobben <rwobben@hotmail.com> wrote:
> Hello,
>
> I changed from ruby koans to rubymonks.
>
> Now I have to make a method which can substract any number of numbers.
>
> So I tried this
>
> def subtract(*numbers)
>   numbers.inject(0) { |sum, number| sum - number }
> end
>
> but that won't work  subtract ( 4,5) gives -9  when -1 is the right answer.
>
> Can anyone give me a tip for a better answer.

inject(0) will pass 0 as the first accumulator. If you don't pass the
0, then inject will use the first element in the array as the first
accumulator, which is what you want I think.

Jesus.