# descendant(_:_:) Returns a specific descendant of the reflected subject, or `nil` if no such descendant exists. ``` func descendant(_ first: any MirrorPath, _ rest: any MirrorPath...) -> Any? ``` ## Parameters `first` The first mirror path component to access. `rest` Any remaining mirror path components. ## Return Value The descendant of this mirror specified by the given mirror path components if such a descendant exists; otherwise, `nil`. ## Discussion Pass a variadic list of string and integer arguments. Each string argument selects the first child with a matching label. Each integer argument selects the child at that offset. For example, passing `1, "two", 3` as arguments to `myMirror.descendant(_:_:)` is equivalent to: ``` var result: Any? = nil let children = myMirror.children if let i0 = children.index( children.startIndex, offsetBy: 1, limitedBy: children.endIndex), i0 != children.endIndex { let grandChildren = Mirror(reflecting: children[i0].value).children if let i1 = grandChildren.firstIndex(where: { $0.label == "two" }) { let greatGrandChildren = Mirror(reflecting: grandChildren[i1].value).children if let i2 = greatGrandChildren.index( greatGrandChildren.startIndex, offsetBy: 3, limitedBy: greatGrandChildren.endIndex), i2 != greatGrandChildren.endIndex { // Success! result = greatGrandChildren[i2].value } } } ``` This function is suitable for exploring the structure of a mirror in a REPL or playground, but is not intended to be efficient. The efficiency of finding each element in the argument list depends on the argument type and the capabilities of the each level of the mirror’s `children` collections. Each string argument requires a linear search, and unless the underlying collection supports random-access traversal, each integer argument also requires a linear operation. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)