我如何判断我从-valueForKey返回的NSNumber:最初是int还是float？

Question

原因是我必须回到房产中的确切价值.所以如果它是一个浮点数,我想调用-floatValue.但如果它是一个int,我想调用-intValue.

NSNumber是否记得它是如何初始化的？

Answer 1

NSNumber与CFNumber进行免费桥接(参见CFNumber参考文献顶部的文本).所以你可以使用CFNumberGetType.例如

- (void)logTypeOf:(NSNumber *)number
{
    switch(CFNumberGetType((CFNumberRef)number))
    {
        case kCFNumberSInt8Type:    NSLog(@"8bit signed integer"); break;
        case kCFNumberSInt16Type:   NSLog(@"16bit signed integer"); break;
        case kCFNumberSInt32Type:   NSLog(@"32bit signed integer"); break;

        /* ... etc, for all of:
           kCFNumberSInt64Type
           kCFNumberFloat32Type
           kCFNumberFloat64Type
           kCFNumberCharType
           kCFNumberShortType
           kCFNumberIntType
           kCFNumberLongType
           kCFNumberLongLongType
           kCFNumberFloatType
           kCFNumberDoubleType
           kCFNumberCFIndexType
           kCFNumberNSIntegerType
           kCFNumberCGFloatType
        */
   }
}

编辑:更仔细地查看文档,CFNumberIsFloatType似乎完全符合您的要求而没有复杂性.所以:

if(CFNumberIsFloatType((CFNumberRef)number))
{
    NSLog(@"this was a float");
}
else
{
    NSLog(@"this was an int");
}