[Solved] You have a dictionary var inventory = ["apple": 3, "banana": 5]. Write code to safely add 2 to the count of "orange", even if it doesn't exist yet, using dictionary default values.... | Swift

Swift - Collections

You have a dictionary var inventory = ["apple": 3, "banana": 5]. Write code to safely add 2 to the count of "orange", even if it doesn't exist yet, using dictionary default values. What is the correct way?

Ainventory["orange"] = inventory["orange"]! + 2

Binventory["orange"] = inventory["orange"] ?? 0 + 2

Cinventory.updateValue(inventory["orange"]! + 2, forKey: "orange")

Dinventory["orange"] = inventory["orange", default: 0] + 2

Step-by-Step Solution

Solution:

Step 1: Understand safe addition with default
Using inventory["orange", default: 0] returns 0 if "orange" key is missing.
Step 2: Increment value safely
Adding 2 to this default value and assigning back to inventory["orange"] updates or creates the key safely.
Final Answer:
inventory["orange"] = inventory["orange", default: 0] + 2 -> Option D
Quick Check:
dict[key] = dict[key, default: 0] + value for safe increments [OK]

Quick Trick: Use dict[key] = dict[key, default: 0] + amount to add safely [OK]

Common Mistakes:

Force unwrapping missing keys causing crash
Using += on read-only default subscript
Using updateValue without checking for nil

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What is the correct way?

Step 1: Understand safe addition with default

Step 2: Increment value safely

Final Answer:

Quick Check:

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