From: Hal Fulton <hal9000@...>
Date: 2003-08-29T00:48:56+09:00
Subject: #collect with block modifying receiver

Hello, all...

I'm wondering what should be the behavior of collect when the block
modifies the receiver.

I don't recall thinking about this before, but I would have said
that the collect always returns as many items as the array had
at the time of the call.

Has this somehow changed since 1.6.*?

The reason I ask is the email (below) I got from Jonathan Lim.
The randomize methods on page 152/153 of _The Ruby Way_ do not
work. It's possible they never did, but I find that hard to
believe.

I don't have an old Ruby around, or I'd test it.

The original line in randomize, of course, read as follows:

   arr.collect { arr.slice!(rand arr.length) }

Thanks to you who reply, and thanks again to Jonathan.

Cheers,
Hal


-------- Original Message --------
Subject: Randomizing an Array Errata?
Date: Thu, 28 Aug 2003 15:12:45 +0100
From: Jonathan Lim <jhgl@dial.pipex.com>
To: hal9000@hypermetrics.com

Hi,

On p.153 of the Ruby Way

Should it not read this?

def randomize
	arr = self.dup
	self.collect { arr.slice!(rand arr.length) }
end

def randomize!
	arr = self.dup
	result = self.collect { arr.slice!(rand arr.length) }
	self.replace result
end

Cheers,
Jon