Instance Method

prefix(while:)

Returns a subsequence containing the initial elements until predicate returns false and skipping the remaining elements.

Declaration

func prefix(while predicate: (Character) throws -> Bool) rethrows -> Substring

predicate: A closure that takes an element of the sequence as its argument and returns true if the element should be included or false if it should be excluded. Once the predicate returns false it will not be called again.

Complexity: O(n), where n is the length of the collection.