From: Sander Land <sander.land@...>
Date: 2006-09-04T01:43:40+09:00
Subject: Re: Happy Numbers (#93)

On 9/3/06, Phrogz <gavin@refinery.com> wrote:
> Sander Land wrote:
> > class Array
> >   def sum
> >     inject(0){|a,b| a+b}
> >   end
> > end
>
> For a little more speed, try instead:
>
> class Array
>   def sum
>     inject{ |a,b| a+b }
>   end
> end

Is that really so much faster? Worth breaking on empty arrays?
Just had to test if there was any performance difference, results:

      user     system      total        real
inject(0)  20.320000   5.430000  25.750000 ( 34.486938)
inject     20.450000   5.350000  25.800000 ( 30.152165)
inject &:+ 37.860000   5.690000  43.550000 ( 45.670349)
each       11.130000   3.460000  14.590000 ( 15.042142)
C           0.020000   0.000000   0.020000 (  0.019815)

so inject(0) vs inject doesn't really matter.
code: http://pastie.caboo.se/11534  (and yes i know the C code doesn't
handle bignums)

@Robert: you mean the thread "for performance, write in C" ?  ;)