Stefano Crocco
2/21/2007 6:17:00 PM
Alle mercoledì 21 febbraio 2007, niceview ha scritto:
> I'd like to show you some example.
>
> --
>
> def t1(str)
> str = str.gsub(/1/, "!")
> end
>
> def t2(str)
> str.gsub!(/1/, "!")
> end
>
> a = "123"
> p t1(a) # => "!23"
> p a # => "123"
>
> a = "123"
> p t2(a) # => "!23"
> p a # => "!23"
>
> --
>
> Is 'str' variable a local variable in 't2' method?
>
> Why 'str.gsub!(/1/, "!")' change 'a' variable?
Because gsub! changes its argument. While str is a local variable in t2, the
object it references is the same that a references. You can see this adding
the line
puts str.object_id
in the definition of t2 and the line
puts a.object_id
after a='123'. You'll see that str and a are the same thing.
I hope this helps
Stefano