How to convert String according to its content in Swift?

Question

I have a variable of type String in Swift, its content may be as follows:

var str:String = "45.7" //content is of float type

Or the contents may be:

var str:String = "45" //content is of int type

the content may also be of any other type having more numbers and/or decimals. How could I convert the String accordingly?

The variable is only one, there aren't two variables. And the value of the variable is not fixed, if it contains a decimal or not, it may contain a decimal point number or may not. The single variable may have the above possibilities of data stored.

Possible duplicate of [Swift - Converting String to Int](http://stackoverflow.com/questions/24115141/swift-converting-string-to-int) — FelixSFD, Dec 17 '16 at 08:27

Nirav D · Accepted Answer · 2016-12-17T09:18:15.453

1

You can use if let for that.

var str:String = "45.7" //content is of float type
if let _ = str.range(of: "."), let floatValue = Float(str)  {        
    //Execute if string contains float value
    print(floatValue)
}
else if let intValue = Int(str) {
    //Execute if string contains integer value
    print(intValue)
}

edited Dec 17 '16 at 09:18

answered Dec 17 '16 at 08:46

Nirav D

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If the string is "45", the conversion to `Float` still succeeds, although it would be an integer – FelixSFD Dec 17 '16 at 08:48
@FelixSFD Also check the edited answer with more detail, because if string contains multiple `.` it will crash, now it will not. – Nirav D Dec 17 '16 at 09:02

Vatsal Manot · Answer 2 · 2016-12-17T08:48:18.330

0

Via:

Float(str)

and:

Int(str)

respectively.

Or, if you don't know the numeric type at compile-time:

NumberFormatter().number(from: str)

edited Dec 17 '16 at 08:48

answered Dec 17 '16 at 08:34

Vatsal Manot

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it is not fixed whether the value of the variable contains decimal or not. and the variable is single, The value of the variable changes according to user input. the second variable i put in the question is just to show the possibilities the String can contain. – Mohit Mishra Dec 17 '16 at 08:38
@MohitMishra: What you want is `NSNumber`. – Vatsal Manot Dec 17 '16 at 08:45
I just want to convert the string accordingly. And the contents of the string are not predetermined, it depends on user's input. If the user inputs a decimal point number, then i want to change it to a float type, And if the user simply enters a non-decimal point number, then i want to change it into Int type. – Mohit Mishra Dec 17 '16 at 08:48

score 0 · Answer 3 · answered Dec 17 '16 at 08:53

In your playground:

func isContainPoint(_ string:String) -> Bool {

    if string.contains(".") {

        return true
    }else {

        return false
    }
}

var str1:String = "45.7" //content is of float type

var str2:String = "45" //content is of int type



if isContainPoint(str1) {

    print("\(Float(str1)!)")
}else {
    print("\(Int(str1)!)")
}

if isContainPoint(str2) {

    print("\(Float(str2)!)")
}else {
    print("\(Int(str2)!)")
}

Result is:

45.7
45

How to convert String according to its content in Swift?

3 Answers3