Ruby variable assignment

Question

Can someone explain this behavior:

a = b = c = 1, 2, 3 
a # => [1, 2, 3]
b # => 1
c # => 1

In the assignment a = b = c = 1, 2, 3, the variables a, b, and c should be assigned [1, 2, 3]. Any idea?

Answer 1

Can someone explain why is this happening

@shivam already answered the question, but adding some parentheses might clarify things even more.

a = b = c = 1, 2, 3

is interpreted as:

a = [(b = (c = 1)), 2, 3]

The expression is evaluated in this order:

           c = 1
      b = (     )
a = [(           ), 2, 3]

the variables a, b, and c should be assigned [1, 2, 3]

To get the expected result, you could write:

a = b = c = [1, 2, 3]

which is interpreted as:

a = (b = (c = [1, 2, 3]))

and evaluated in this order:

          c = [1, 2, 3]
     b = (             )
a = (                   )