From: James Gray <james@...>
Date: 2009-01-20T22:49:59+09:00
Subject: [ruby-core:21461] Re: Array concat loops sometimes taking large amounts of "system" time.

On Jan 20, 2009, at 6:48 AM, Ron Mayer wrote:

>   a = [1,2,3,4,5];
>   b=[];
>   puts Benchmark.measure{ (1..10000000).each{b.concat(a)}}

This code slowly builds up a very large Array:

 >> a = (1..5).to_a
=> [1, 2, 3, 4, 5]
 >> b = [ ]
=> []
 >> b.concat(a)
=> [1, 2, 3, 4, 5]
 >> b.concat(a)
=> [1, 2, 3, 4, 5, 1, 2, 3, 4, 5]

The time loss may come from memory allocation.

James Edward Gray II