How to convert an NSString into an NSNumber

Question

How can I convert a NSString containing a number of any primitive data type (e.g. int, float, char, unsigned int, etc.)? The problem is, I don't know which number type the string will contain at runtime.

I have an idea how to do it, but I'm not sure if this works with any type, also unsigned and floating point values:

long long scannedNumber;
NSScanner *scanner = [NSScanner scannerWithString:aString];
[scanner scanLongLong:&scannedNumber]; 
NSNumber *number = [NSNumber numberWithLongLong: scannedNumber];

Thanks for the help.

Answer 1

I wanted to convert a string to a double. This above answer didn't quite work for me. But this did: How to do string conversions in Objective-C?

All I pretty much did was:

double myDouble = [myString doubleValue];

Answer 2

I know this is very late but below code is working for me.

Try this code

NSNumber *number = @([dictionary[@"keyValue"] intValue]]);

This may help you. Thanks

Answer 3

extension String {

    var numberValue:NSNumber? {
        let formatter = NumberFormatter()
        formatter.numberStyle = .decimal
        return formatter.number(from: self)
    }
}

let someFloat = "12.34".numberValue

Answer 4

you can also do like this code 8.3.3 ios 10.3 support

[NSNumber numberWithInt:[@"put your string here" intValue]]

Answer 5

What about C's standard atoi?

int num = atoi([scannedNumber cStringUsingEncoding:NSUTF8StringEncoding]);

Do you think there are any caveats?

Answer 6

Use an NSNumberFormatter:

NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
f.numberStyle = NSNumberFormatterDecimalStyle;
NSNumber *myNumber = [f numberFromString:@"42"];

If the string is not a valid number, then myNumber will be nil. If it is a valid number, then you now have all of the NSNumber goodness to figure out what kind of number it actually is.