Swift - Collections
What happens if you create a Swift dictionary with duplicate keys in the literal?
let dict = ["x": 1, "y": 2, "x": 3]
What happens if you create a Swift dictionary with duplicate keys in the literal?
hard📝 Conceptual Q10 of 15
Step-by-Step Solution
Solution:
Step 1: Understand dictionary literal behavior
Swift allows duplicate keys in literals but keeps the last value assigned to that key.Step 2: Check for errors
No compile or runtime error occurs; the dictionary stores the last value for "x".Final Answer:
The last value for the duplicate key is used -> Option DQuick Check:
Duplicate keys keep last value in Swift dictionary [OK]
Quick Trick: Duplicate keys keep last value in dictionary literal [OK]
Common Mistakes:
- Expecting compiler error
- Thinking first value is kept
- Assuming runtime error occurs
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