From: Martin DeMello <martindemello@...>
Date: 2005-01-28T17:40:54+09:00
Subject: Re: Array::uniq { block } ?

itsme213 <itsme213@hotmail.com> wrote:
> "Martin DeMello" <martindemello@yahoo.com> wrote in message
> 
> > A uniq_by would probably cover
> > most of the use cases anyway.
> 
> Why a different method? Is that the way it is done elsewhere? Why not
> def uniq
>     if block_given?
>         ... less_efficient
>     else default_way
> end

By analogy with sort and sort_by

a.uniq_by {|i| i[1]} would work like uniq, but hashing i[i] rather than
i. a.uniq {|i,j| f(i,j) == true } would be the generalised method, but
as noted that's O(n^2) rather than O(n). (Also I'm not sure it'd be
algorithmically sound - you could introduce order dependencies with a
sufficiently adversarial comparison function.)

martin