Instance Method

prefix(_:)

Returns a sequence, up to the specified maximum length, containing the initial elements of the sequence.

Declaration

func prefix(_ maxLength: Int) -> PrefixSequence<AnyIterator<Element>>

Parameters

maxLength

The maximum number of elements to return. The value of maxLength must be greater than or equal to zero.

Return Value

A sequence starting at the beginning of this sequence with at most maxLength elements.

Discussion

If the maximum length exceeds the number of elements in the sequence, the result contains all the elements in the sequence.

let numbers = [1, 2, 3, 4, 5]
print(numbers.prefix(2))
// Prints "[1, 2]"
print(numbers.prefix(10))
// Prints "[1, 2, 3, 4, 5]"

Complexity: O(1)