From: Stefano Crocco <stefano.crocco@...>
Date: 2013-02-23T18:06:52+09:00
Subject: Re: range is not assigning to the splat variable.

On Saturday 23 February 2013 Love U Ruby wrote
> Why splat variable couldn't take in the below two code the "range" ->
> (1..8)?
> 
> means why a gives []?
> 
> *a,b = (1..8)
> #=> 1..8
> b
> #=> 1..8
> a
> #=> []
> 
> means why b gives []?
> 
> a,*b = (1..8)
> #=> 1..8
> a
> #=> 1..8
> b
> #=> []
> 
> --
> Posted via http://www.ruby-forum.com/.

In both case, the right hand side of the assignment is a single object. When 
this happens, the object can be assigned to only one of the variables on the 
left hand side of the assignment. In your first example, the * before a tells 
that a can contain any number of values (including no values). So ruby assign 
the only availlable value (the range) to b and assign an empty array to a. In 
the second case, it's the opposite.

Arrays and objects responding to #to_ary are an exception to the rule, as they 
are automatically distributed among the variables:

*a,b = (1..8).to_a
#=> [1,2,3,4,5,6,7,8]
b
#=> 8
a
#=> [1,2,3,4,5,6,7]

You can obtain what you want without explicitly converting the range to an 
array using the splat operator:

*a,b=*(1..8)
#=> [1,2,3,4,5,6,7,8]
b
#=> 8
a
#=> [1,2,3,4,5,6,7]

Stefano