Swift Collection Protocols

Swift Collection Protocols

Arrays, Sets and Dictionaries conform to Sequence and Collection, which provide common APIs like count and isEmpty.

Common APIs

Use count and isEmpty to check collection size.

let arr = [1, 2, 3]
print(arr.count)
print(arr.isEmpty)
let s: Set<Int> = [1, 2, 3]
print(s.contains(2))
print(s.isEmpty)

This example shows shared operations exposed via collection protocols.

Indices

Use the indices property to iterate valid positions.

let arr = [10, 20, 30]
for i in arr.indices {
  print("index: \(i), value: \(arr[i])")
}