From: Kyle Schmitt <kyleaschmitt@...>
Date: 2007-07-20T07:05:52+09:00
Subject: Re: Hash of arrays - whats going on?

default just lets you return a default value if the request key
doesn't exist, it's not _supposed_ to change the state of the hash.

What was happening is an array was presented to you when you called
h['foo'], and you were putting a value in it, but the array was never
saved to a variable, so it went away.

With the original code try the following code, it may help you understand:
h['foo'] << 10
puts h.length
h[foo'] << 20
puts h.length