Returns an array containing the non-
nil results of calling the given transformation with each element of this sequence.
- Xcode 9.3+
- Swift Standard Library
A closure that accepts an element of this sequence as its argument and returns an optional value.
An array of the non-
nil results of calling
transform with each element of the sequence.
Use this method to receive an array of non-optional values when your transformation produces an optional value.
In this example, note the difference in the result of using
compact with a transformation that returns an optional
Complexity: O(m + n), where n is the length of this sequence and m is the length of the result.