Checking if NSString is Integer

Question

Possible Duplicate:
NSString is integer?

I'm looking to see if a string is ONLY numbers. Basically:

if (string is integer):
   #do whatever
else:
   #error

How would I do this? Thanks!

Answer 1

I have used [NSCharacterSet decimalDigitCharacterSet]. Definitely works well.

NSCharacterSet* notDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];

if ([newString rangeOfCharacterFromSet:notDigits].location == NSNotFound)
{
// newString consists only of the digits 0 through 9
}

Answer 2

-(BOOL)isANumber:(NSString *)string{
    NSPredicate *numberPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES '^[0-9]+$'"];
    return [numberPredicate evaluateWithObject:string];
}