判斷字符串NSString是不是整形或者浮點型

//判斷字符串是否爲整形
- (BOOL)isPureInt:(NSString*)string{
    NSScanner* scan = [NSScanner scannerWithString:string];
    int val;
    return [scan scanInt:&val] && [scan isAtEnd];
}

//判斷字符串是否爲浮點形：
- (BOOL)isPureFloat:(NSString*)string{
    NSScanner* scan = [NSScanner scannerWithString:string];
    float val;
    return[scan scanFloat:&val] && [scan isAtEnd];
}