[英]Proper way for casting uint16 to int16 in Go
Bitwise manipulation and Go newbie here :DI am reading some data from sensor with Go and I get it as 2 bytes - let's say 0xFFFE
. 按位操作和Go新手在这里:DI正在使用Go从传感器读取一些数据,我将其获取为2个字节-假设0xFFFE
。 It is easy too cast it to uint16 since in Go we can just do uint16(0xFFFE)
but what I need is to convert it to integer, because the sensor returns in fact values in range from -32768 to 32767. Now I thought "Maybe Go will be this nice and if I do int16(0xFFFE)
it will understand what I want?" 也很容易将其强制转换为uint16,因为在Go中我们可以执行uint16(0xFFFE)
但我需要将其转换为整数,因为传感器返回的值实际上是-32768到32767。现在,我想“也许Go会很不错,如果我执行int16(0xFFFE)
,它将明白我想要什么吗?” , but no. , 但不是。 I ended up using following solution (I translated some python code from web): 我最终使用了以下解决方案(我从网络上翻译了一些python代码):
x := 0xFFFE
if (x & (1 << 15)) != 0 {
x = x - (1<<16)
}
It seems to work, but A) I am not entirely sure why, and B) It looks a bit ugly to what I imagined should be a trivial solution for casting uint16 to int16. 它似乎可行,但是A)我不确定为什么,B)我认为应该是将uint16转换为int16的简单解决方案,这看起来有点难看。 Could anyone give me a hand and clarify why this is only way to do this? 谁能帮我一下,弄清楚为什么这是唯一的方法? Or is there any other possible way? 还是还有其他可能的方法?
But what you want works, "Go is nice": 但是您想要的是,“ Go很好”:
ui := uint16(0xFFFE)
fmt.Println(ui)
i := int16(ui)
fmt.Println(i)
Output (try it on the Go Playground ): 输出(在Go Playground上尝试):
65534
-2
int16(0xFFFE)
doesn't work because 0xfffe
is an untyped integer constant which cannot be represented by a value of type int16
, that's why the the compiler complains. int16(0xFFFE)
不起作用,因为0xfffe
是无类型整数常数不能由类型的值来表示int16
,这就是为什么该编译器会抱怨。 But you can certainly convert any uint16
non-constant value to int16
. 但是您当然可以将任何uint16
非恒定值转换为int16
。
See possible duplicates: 查看可能的重复项:
Golang: on-purpose int overflow Golang:故意int溢出
Does go compiler's evaluation differ for constant expression and other expression 对于常量表达式和其他表达式,去编译器的评估是否有所不同
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