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

Parameters

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.

Discussion

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

See Also

Getting Substrings

subscript(Range<String.Index>) -> Substring

Accesses a contiguous subrange of the collection’s elements.

subscript<R>(R) -> Substring

Accesses the contiguous subrange of the collection’s elements specified by a range expression.

func prefix(Int) -> Substring

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

func prefix(through: Index) -> Substring

Returns a subsequence from the start of the collection through the specified position.

func prefix(upTo: Index) -> Substring

Returns a subsequence from the start of the collection up to, but not including, the specified position.

func suffix(Int) -> Substring

Returns a subsequence, up to the given maximum length, containing the final elements of the collection.

func suffix(from: Index) -> Substring

Returns a subsequence from the specified position to the end of the collection.