Instance Method

lastIndex(of:)

Returns the last index where the specified value appears in the collection.

Declaration

func lastIndex(of element: UTF16.CodeUnit) -> String.Index?

Parameters

element: An element to search for in the collection.

Return Value

The last index where element is found. If element is not found in the collection, this method returns nil.

Discussion

After using lastIndex(of:) to find the position of the last instance of a particular element in a collection, you can use it to access the element by subscripting. This example shows how you can modify one of the names in an array of students.

var students = ["Ben", "Ivy", "Jordell", "Ben", "Maxime"]
if let i = students.lastIndex(of: "Ben") {
    students[i] = "Benjamin"
}
print(students)
// Prints "["Ben", "Ivy", "Jordell", "Benjamin", "Max"]"

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