From: Christer Nilsson <janchrister.nilsson@...>
Date: 2005-12-14T08:34:50+09:00
Subject: Re: Array.invert

Simon wrote:
> 
> i will give you two:
> 
> class Array
>    def invert
>      zip([*(0...size)]).inject([]){|s, b| (b.first || []).each{|i| (s[i]
> ||= []) << b.last}; s}
>    end
> end
> 
> or (even worse):
> 
> class Array
>    def invert
>      Array.new(flatten.compact.max.succ){|i|
> zip([*(0...size)]).find_all{|b, j| b && b.include?(i)}.transpose[1]}
>    end
> end

I didn't know invert was so complex that ten keywords were needed!
The more keywords, the more cycles.
My original old fashioned fortran style polyliner is still quickest :-)

Christer

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