Finding out whether a string is numeric or not

Question

How can we check if a string is made up of numbers only. I am taking out a substring from a string and want to check if it is a numeric substring or not.

NSS         


        

Answer 1

Yet another option:

- (BOOL)isValidNumber:(NSString*)text regex:(NSString*)regex {
    @try {
        NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
        return [predicate evaluateWithObject:text];
    }
    @catch (NSException *exception) {
        assert(false); 
        return NO;
    }
}

Usage example:

BOOL isValid = [self isValidNumber:@"1234" regex:@"^[0-9]+$"];