From: Sebastian Hungerecker <sepp2k@...>
Date: 2008-09-26T18:21:27+09:00
Subject: Re: How does Array's each method change its elements ?

w wg wrote:
> I want to know how does Array's each method (block) change its elements ?

It doesn't. You do.

> b = a.each  { |x| x + 1}

This executes "x + 1" for every element in the array. Compare the following:
x = 5
x + 1
p x
x is still 5. The expression x+1 does not change the value of x.

> b = a.each { |x|  x <<  "-"  }

x = "foo"
x << "-"
p x
Prints "foo-" because << does modify the receiver. I.e. after calling << "-" 
the string will contain a "-", so that's what's happening to each element in 
the array.

Another note: each returns the receiver, so if you do
b = a.each {...}
b and a will point to the exact same array no matter what happens in the block 
(unless you use break inside the block).

HTH,
Sebastian
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