OC 判断一个字符串是不是int、float、double

//整形判断(整形返回yes ,否则为no)
- (BOOL)isPureInt:(NSString *)string{
    NSScanner* scan = [NSScannerscannerWithString:string];
    int val;
    return [scan scanInt:&val] && [scan isAtEnd];
}
 
//浮点形判断(整形/浮点型等数字均会返回YES,其他为no):
- (BOOL)isPureFloat:(NSString *)string{
    NSScanner* scan = [NSScannerscannerWithString:string];
    float val;
    return [scan scanFloat:&val] && [scan isAtEnd];
}
 
//浮点形判断(整形/浮点型等数字均会返回YES,其他为no):
- (BOOL)isPureDouble:(NSString *)string{
    NSScanner* scan = [NSScannerscannerWithString:string];
    double val;
    return [scan scanDouble:&val] && [scan isAtEnd];
}