From: Timothy Goddard <interfecus@...>
Date: 2006-03-08T19:53:41+09:00
Subject: Re: ridiculous behavoir of Array#push and Array#clear

This is because arr1 is storing a _reference_ to arr2. If you want to
avoid this behaviour you could use any of the following:

arr1 += arr2 (generates new array, old arr1 is now garbage)
arr1 << arr2.dup (copies arr2, the copy is stored as an element of
arr1)
(arr1 << arr2).flatten! (ideal, but most verbose)

The first two generate new objects. I believe the third doesn't (I may
be wrong). Take your pick.