Assign value only if not nil

Question

I can replace this:

le_one = load_le_other() unless le_one

with this:

le_one ||= load_le_other()

How can I replace this:

le_other = load_le_other()
le_one = le_other if le_other

with something other than this:

le_other = load_le_other()
le_one = le_other || le_one

load_le_other is expensive to call twice. The goal is to make it one liner.

Answer 1

This will assign the appropriate values to both le_one and le_other:

le_one = (le_other = le_load_other()).nil? ? le_one : le_other

It's counterintuitive that you could assign le_one to itself before you've even defined it, but it works.

If you have already defined le_one you can also do this:

le_other = le_load_other()&.tap { |val| le_one = val }

The &. causes the tap (and its block) to only execute if le_load_other() returns a non-nil value.

Answer 2

If load_le_other() cannot return false,

le_one = le_other = load_le_other()

Note that if

le_other = load_le_other()
  #=> nil
le_one = le_other if le_other
  # le_one = nil if nil
  #=> nil 

Answer 3

Replace with this:

le_one = load_le_other() || le_one