From: Josselin <josselin@...>
Date: 2007-03-26T05:00:05+09:00
Subject: Re: splitting an array into sub_arrays ...need advice

On 2007-03-25 19:00:00 +0200, Olivier Renaud <o.renaud@laposte.net> said:

> Le dimanche 25 mars 2007 17:50, Josselin a �crit�:
>> I have an array similar to this example  (after sorting it on a[i][1]
>> and a[i][2])
>> 
>> start_array = [ [1, 1, 1, 0], [2, 1, 1, 0], [3, 1, 1, 0], [4, 1, 2, 0],
>> [5, 1, 2, 0], [6, 2, 1, 0], [7, 2, 1, 0], [8, 2, 2, 0], [9, 2, 2, 0],
>> [10, 2, 3, 0] ]
>> 
>> I am trying to split it, into sub_arrays according to similarelements
>> a[i][1] and a[i][2] ,
>> to get another array like this one :
>> 
>> resulting_array = [  [[1, 1, 1, 0], [2, 1, 1, 0], [3, 1, 1, 0]]  ,
>> [[4, 1, 2, 0], [5, 1, 2, 0]]  ,  [[6, 2, 1, 0], [7, 2, 1, 0]]  , [[8,
>> 2, 2, 1], [9, 2, 2, 0]]  , [[10, 2, 3, 0]]   ]
> 
> There is a way to group objects easily with Enumerable#partition_by, in the
> 
> Facets gem.
> 
> irb(main):001:0> require 'facets'
> irb(main):002:0> require 'enumerable/partition_by'
> irb(main):006:0> start_array.partition_by {|ary| ary[1..2]}
> => {[1, 2]=>[[4, 1, 2, 0], [5, 1, 2, 0]], [2, 1]=>[[6, 2, 1, 0], [7,
> 2, 1,
> 0]], [1, 1]=>[[1, 1, 1, 0], [2, 1, 1, 0], [3, 1, 1, 0]], [2, 3]=>[[10,
> 2, 3,
> 0]], [2, 2]=>[[8, 2, 2, 0], [9, 2, 2, 0]]}
> 
> It may help you for what you are trying to do.

thanks a lot I'll have a look asap