Vishnuvardhan - 8 months ago 44

Swift Question

I want to sort an alphanumeric, but numbers should come at end instead of beginning. for instance

`let array = ["1", "a", "b", "z", "3", "!"]`

let sortedArray = array.sort { (firstObject, secondObject) -> Bool in

firstObject < secondObject

}

["!", "1", "3", "a", "b", "z"]

["a", "b", "z", "1", "3", "!"]

Thanks in advance.

Answer

Here's a solution that works for your case :

**The expected result is :**

- letters first ;
- then numbers ;
- then others ;

Here's a way to do it.

```
// Works with both arrays
var array = ["1", "b", "a", "z", "3", "!"]
//var array = ["1", "b", "A", "Z", "3", "!"]
func isLetter(char: String) -> Bool {
return ("a"..."z").contains(char) || ("A"..."Z").contains(char)
}
func isNumber(char: String) -> Bool {
return Int(char) != nil
}
let letters = array.filter(isLetter).sort{$0.lowercaseString < $1.lowercaseString}
let numbers = array.filter(isNumber).sort{Int($0) < Int($1)}
let others = Array(Set(array).subtract(letters).subtract(numbers)).sort{$0 < $1}
let sortedArray = letters + numbers + others
```

The first array would be

```
["a", "b", "z", "1", "3", "!"]
```

The second would be

```
["A", "b", "Z", "1", "3", "!"]
```

It does what you want. Include unit tests and wrap that inside a method and you're good to go. Buuuut, it's not "clean" at all.