Ruby Academy · Lesson

Default Values and Merging

fetch, merge, dig.

The Problem with nil

Reading a missing key returns nil, which can cause surprises in math or logic. Ruby offers safer ways to handle absence.

h = { a: 1 }
puts h[:b].inspect

fetch returns the value, or raises a clear error if the key is missing. Use it when a key is required.

h = { name: "Ada" }
puts h.fetch(:name)