How to remove nil elements in an array in Swift
arrays tips language If you have an array or a sequence of elements that might contain nil values that you might want
to remove, Swift provides a great higher order function that is pretty handy called compactMap.
Let’s consider that you have an array of names and the requirement is to only keep valid names such that the name is not nil.
let names = ["Kate", nil, "Rohan", "Mohammad", "Joe"]
let validNames = names.compactMap { $0 }If you were to print validNames it will only contain ["Kate", "Rohan", "Mohammad", "Joe"].
Let’s take this example a bit further. If the names array also contains
some empty strings in the sequence you can use filter function to remove them.
You can chain multiple higher order functions together.
let names = ["Kate", nil, "", "Jack", "Rohan", "Mohammad", "", "Joe"]
let validNames = names.compactMap { $0 }.filter { !$0.isEmpty }If you were to print validNames it will contain ["Kate", "Jack", "Rohan", "Mohammad", "Joe"] removing any empty names.
To recap, the compactMap method first removes all nil elements from the array, and then the filter method removes any empty strings that might be in the array.
