Ruby assignment behavior

Question

please help find some article of the next behavior.

a = 'qwer'
a = b
b << 'ty'
puts b # => 'qwerty'
puts a # => 'qwerty'

but if

a = 'qwer'
a = b
b = 'ty'
puts b # => 'ty'
puts a # => 'qwer'

I know why in this case

I know that it works well, but I can not find an explanation - why so

P.S.

if applicable - please give the links to the articles on this subject (or similar Maybe i miss more interesting feature like this).

Thn.

[This answer][1] could be what you are looking for. [1]: http://stackoverflow.com/questions/1872110/is-ruby-pass-by-reference-or-by-value/10974116#10974116 — Yanhao, Jul 25 '13 at 09:26

Marek Lipka · Accepted Answer · 2013-07-25T08:37:13.640

When you do

a = b

you make variable a keep reference to the same object as variable b. That's why when you type:

b << 'ty'

string contained in variable a will also change - this is the same String instance.

On the other hand, let's say you have variable b containing reference to string 'qwer'. If you have:

a = b
b = 'ty'

in first line you assign variable a to the same object as b. In the second line, you assign a new String object to variable b. So in the end both variables have references to different objects.

Ruby assignment behavior

1 Answers1