Instance Method

firstIndex(of:)

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

Declaration

func firstIndex(of element: HasAnchoring) -> Int?

Parameters

element

An element to search for in the collection.

Return Value

The first index where element is found. If element is not found in the collection, returns nil.

Discussion

After using firstIndex(of:) to find the position 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", "Maxime"]
if let i = students.firstIndex(of: "Maxime") {
    students[i] = "Max"
}
print(students)
// Prints "["Ben", "Ivy", "Jordell", "Max"]"

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

See Also

Manipulating Indices

var indices: DefaultIndices<Scene.AnchorCollection>

The indices that are valid for subscripting the collection, in ascending order.

func index(Int, offsetBy: Int) -> Int

Returns an index that is the specified distance from the given index.

func index(Int, offsetBy: Int, limitedBy: Int) -> Int?

Returns an index that is the specified distance from the given index, unless that distance is beyond a given limiting index.

func index(of: HasAnchoring) -> Int?

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

Deprecated
func firstIndex(where: (HasAnchoring) -> Bool) -> Int?

Returns the first index in which an element of the collection satisfies the given predicate.

func formIndex(inout Int, offsetBy: Int)

Offsets the given index by the specified distance.

func formIndex(inout Int, offsetBy: Int, limitedBy: Int) -> Bool

Offsets the given index by the specified distance, or so that it equals the given limiting index.

func formIndex(after: inout Int)

Replaces the given index with its successor.

func distance(from: Int, to: Int) -> Int

Returns the distance between two indices.