From: Stefano Crocco <stefano.crocco@...>
Date: 2007-03-09T17:13:49+09:00
Subject: Re: 2 lines in one...

Alle venerd� 9 marzo 2007, Josselin ha scritto:
> Could I write it in just 1 line ?
>
> find the first value greater than d, in a list (special one :  each
> value is the double of the previous...)
> then give me the index of this value (with special case ...)
>
>       i =
> ([0.5,1.0,2.0,4.0,8.0,16.0,32.0,64.0,128.0,256.0,512.0,1024.0,2048.0].selec
>t {|v| v if v >= d }).first
>
>       zl = d <0.5  ? 0 :
> [0.5,1.0,2.0,4.0,8.0,16.0,32.0,64.0,128.0,256.0,512.0,1024.0,2048.0].index(
>i)
>
> joss

What about this?

a.each_index{|i| break i if a[i] > d}

The only problem is that it returns a if no element greater than d is found. 
You could turn it into a method, though:

def find_greater array, value
  array.each_index{|i| return i if array[i] > value}
  nil
end