Iteration patterns & mutability
Learn common iteration patterns over arrays/dictionaries/sets, use indices and enumerated(), and understand mutability with let vs var (copy-on-write basics).
Why iteration & mutability?
Goal: Iterate safely and clearly over collections, and know when they are mutable. We'll cover arrays, dictionaries, sets, indices, and enumerated(), plus let vs var.
for-in (Array)
for-in iterates directly over elements; simple and clear for arrays.
let nums = [10, 20, 30]
for n in nums {
print("value:", n)
}All lessons in this course
- Arrays, Dictionaries & Sets
- Sets — membership & operations
- Iteration patterns & mutability