Given a dictionary let items = ["pen": 3, "notebook": 0, "eraser": 2], which Swift code correctly creates a new dictionary containing only items with quantity greater than zero?

hard📝 Application Q15 of 15

Swift - Collections

Given a dictionary let items = ["pen": 3, "notebook": 0, "eraser": 2], which Swift code correctly creates a new dictionary containing only items with quantity greater than zero?

Alet filtered = items.compactMap { $0.value > 0 }

Blet filtered = items.filter { $0.key > 0 }

Clet filtered = items.filter { $0.value > 0 }

Dlet filtered = items.map { $0.value > 0 }

Step-by-Step Solution

Solution:

Step 1: Understand filtering dictionary by value
We want to keep pairs where value > 0, so filter with condition on $0.value.
Step 2: Analyze each option
let filtered = items.filter { $0.value > 0 } uses filter with correct condition. let filtered = items.filter { $0.key > 0 } incorrectly compares key (a String) to 0. Options A and C use map/compactMap which transform values, not filter pairs.
Final Answer:
let filtered = items.filter { $0.value > 0 } -> Option C
Quick Check:
Filter dictionary by value > 0 = let filtered = items.filter { $0.value > 0 } [OK]

Quick Trick: Use filter with $0.value condition to keep matching pairs [OK]

Common Mistakes:

Filtering by key instead of value
Using map instead of filter for selection
Using compactMap which changes type, not filters

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More Swift Quizzes

Given a dictionary let items = ["pen": 3, "notebook": 0, "eraser": 2], which Swift code correctly creates a new dictionary containing only items with quantity greater than zero?

Step 1: Understand filtering dictionary by value

Step 2: Analyze each option

Final Answer:

Quick Check:

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