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Difference between arrays and dictionaries in Swift
Updated May 6, 2026
Short answer
Arrays are ordered collections; dictionaries are key-value pairs.
Deep explanation
Arrays preserve order and use index access. Dictionaries store unique keys for fast lookup.
Real-world example
Use arrays for feed lists and dictionaries for caching user data.
Common mistakes
- Assuming dictionary order is stable.
Follow-up questions
- Are dictionaries ordered in Swift?
- When to use Set instead of Array?