From: Jacob Fugal <lukfugl@...>
Date: 2006-11-16T00:49:13+09:00
Subject: Re: Design problem with 'inject'

On 11/14/06, Gary Boone <dr@garyboone.com> wrote:
>    arr.inject(0) do |sum, i|
>                    next if (i==3)
>                    sum += i
>                  done

Others have already posted clarifying the semantics of inject and
proposing alternate solutions, so I won't bother with that. I just
wanted to point out another alternate:

  arr.select{ |i| i != 3 }.inject(0){ |sum, i| sum + i }

I like to use block-taking functions on Enumerables like unix pipes
and let the body of each block do the simplest thing possible.

The only potential drawback to breaking the filter apart like this is
that the current implementation of ruby turns this into two loops. If
your array is large, this can be a problem. But for most cases where
you're not doing number crunching, the inefficiency is negligible.

Just another possibility...

Jacob Fugal