Why am I getting objects printed twice?

Question

When I am in irb or in rails and I create some iteration with each, I am getting the whole struct printed again in my terminal or inside the browser. Example:

Answer 1

Every expression in Ruby returns a value; in irb, the value returned by the expression you've just executed is displayed after =>.

The return value of Enumerable::each is the object that called each - in this case, the array [1,2,3,4]