Swift 2 Using "contains" function with multidimensional array

Question

I am trying to do the simple task of finding if a (string) element exists in an array. The "contains" function works with a one-dimensional array, but not in a 2-dimensional array. Any suggestions? (Documentation on this function appears to be sparse, or I don't know where to look.)

Answer 1

The Swift standard library does not have "multi-dimensional arrays", but if you refer to "nested arrays" (i.e. an array of arrays) then a nested contains() would work, for example:

let array = [["a", "b"], ["c", "d"], ["e", "f"]]
let c = array.contains { $0.contains("d") }
print(c) // true

Here the inner contains() method is

public func contains(element: Self.Generator.Element) -> Bool

and the outer contains() method is the predicate-based

public func contains(@noescape predicate: (Self.Generator.Element) throws -> Bool) rethrows -> Bool

which returns true as soon as the given element is found in one of the inner arrays.

This approach can be generalized to deeper nesting levels.

Answer 2

Updated for Swift 3

The flatten method has been renamed to joined now. So the usage would be

[[1, 2], [3, 4], [5, 6]].joined().contains(3) // true

---

For multi-dimensional array, you can use flatten to decrease one dimension. So for two-dimensional array:

[[1, 2], [3, 4], [5, 6]].flatten().contains(7) // false

[[1, 2], [3, 4], [5, 6]].flatten().contains(3) // true