From: timsuth@... (Tim Sutherland)
Date: 2004-01-17T15:15:04+09:00
Subject: Re: Concatenating variable number of Arrays ?

In article <1074168191.4130.26.camel@lambda.eavesdrop.ping.de>, Florian Frank
wrote:
>On Wed, 2004-01-14 at 16:33, Johan Holmberg wrote:
>> The best way I have found until now, of doing what I want is
>> 
>>     arr2 = arr1.inject([]) {|acc,x| acc.concat x}
>
>You can also use "+" here:
>
>arr2 = arr1.inject([]) { |a,x| a + x }
[...]

If you're going to do this then you might want to define `sum':
  class Array
    def sum(start)
    	inject(start) { |a, x| a + x }
    end
  end

Then you can do
  arr2 = arr1.sum([])

Of course, as Robert Klemme says, this creates many temporary arrays.