Returns an index that is the specified distance from the given index.
SDK
- Xcode 8.0+
Framework
- Swift Standard Library
Declaration
Parameters
iA valid index of the array.
distanceThe distance to offset
i.
Return Value
An index offset by distance from the index i. If distance is positive, this is the same value as the result of distance calls to index(after:). If distance is negative, this is the same value as the result of abs(distance) calls to index(before:).
Discussion
The following example obtains an index advanced four positions from an array’s starting index and then prints the element at that position.
let numbers = [10, 20, 30, 40, 50]
let i = numbers.index(numbers.startIndex, offsetBy: 4)
print(numbers[i])
// Prints "50"
The value passed as distance must not offset i beyond the bounds of the collection.