Quick Answer
Accessing non-existent hash keys
Understanding the Issue
Ruby raises KeyError when accessing missing keys with fetch() or when trying to reference undefined keys with certain methods.
The Problem
This code demonstrates the issue:
Ruby
Error
# Problem: Missing key
h = { a: 1 }
h.fetch(:b) # KeyErrorThe Solution
Here's the corrected code:
Ruby
Fixed
# Solution 1: Default value
h.fetch(:b, 0) # => 0
# Solution 2: Safe access
h[:b] || "default"
# Solution 3: has_key? check
h[:b] if h.key?(:b)Key Takeaways
Always handle missing keys gracefully.