From: Dave Thomas <dave@...>
Date: 2008-02-07T11:46:20+09:00
Subject: Re: Array Practice


On Feb 6, 2008, at 8:15 PM, Christopher Dicely wrote:

> Anytime I  want to "build up" something from an existing Enumerable
> object (Array, etc.) in Ruby, I usually look to inject or collect; the
> most elegant of the way I've come up with of doing exactly what you
> want uses ==, *, uniq, collect, find_all, and size, and the function
> body fits on a single line without semi-colons.  (I'm not holding up
> that it is a one-liner as a strength, just as a description.)

Ruby 1.9 lets you do it with a few less methods... (I'll give it away  
because I'm fairly sure the OP won't be using 1.9). Of course, it only  
works on immediate values...

[1,2,3,1,2,2,4,3,2,1].group_by(&:object_id).values



Cheers


Dave