The Book of Ruby

Parallel Assignment

I mentioned earlier that it is possible for a method to return multiple values, separated by commas. Often you will want to assign these returned values to a set of matching variables.

In Ruby, you can do this in a single operation by parallel assignment. This means you can have several variables to the left or an assignment operator and several values to the right. The values to the right will be assigned, in order, to the variables on the left, like this:

parallel_assign.rb

s1, s2, s3 = "Hickory", "Dickory", "Dock"

This ability not only gives you a shortcut way to make multiple assignments; it also lets you swap the values of variables (you just change their orders on either side of the assignment operator):

i1 = 1 i2 = 2 i1, ...