Swift NSString check for Numbers

Question

I have a Array:NSString that look like

[X1],[Tester],[123],[456],[0]

Now i have to check if a position (always the same) is a number or a string
So i tried

 var test = Array[0].intValue
        print(test)

but as [0] is a string it should not return 0 as it also could be [4]

0

is there a way to check if a NSString is a number only (return of true/false would be enough)?

full code example

var Array: [NSString] = ["X1","Fabian","100","200","not avaible"]
/* could also be Array:
var Array0: [NSString] = ["X2","Timo","200","300","300"]
*/
//need to check if Array[4] is a number or not so its "text" or "number"

var test = Array[4].intValue
print(test)

//return 0

please show your exact code, what is the input (not in explanatory terms, but in code terms) - what is currently happening and what exactly do you want to achieve? — luk2302, Oct 31 '15 at 18:15
Possible duplicate of [How to check is a string or number](http://stackoverflow.com/questions/26545166/how-to-check-is-a-string-or-number) — luk2302, Oct 31 '15 at 18:26
as this solution can't work caus NSString has no member toInt — Fabian Boulegue, Oct 31 '15 at 18:27

score 4 · Accepted Answer · answered Oct 31 '15 at 18:27

In swift2: You can use Int(<your variable>) it returns the number if it can cast, else it return nil, and you can check against the returned value.

example using optional condition:

let s = "Some String"
if let _ = Int(s) {
    print("it is a number")
}else{
    print("it is not a number")
}

this example should return "it is not a number"

score 0 · Answer 2 · answered Oct 31 '15 at 19:05

If you wanna collect the indexes where the array elements are numbers, you can use mapping and returning the indexes where the element can be converted to number.

var Array0: [NSString] = ["X1","Fabian","100","200","not avaible"]
var numbersAt: [Int] = Array0.enumerate().map{ (index, number) in
    return (Int(number as String) == nil ? -1 : index)  
}
print("indexes: \(numbersAt)") //numbersAt will have the indexes unless they're not numbers in which case it'll have -1

//Another option will be to filter the array and collect only the number strings 
var numbers = Array0.filter { Int($0 as String) != nil }
print("numbers: \(numbers)")

Swift NSString check for Numbers

2 Answers2