Javascript 数学对象方法 - 负数为零
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/4924842/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Javascript Math Object Methods - negatives to zero
提问by FFish
in Javascript I can't seem to find a method to set negatives to zero?
在 Javascript 中，我似乎找不到将负数设置为零的方法？
-90 becomes 0
-45 becomes 0
0 becomes 0
90 becomes 90
-90 变成 0
-45 变成 0
0 变成 0
90 变成 90
Is there anything like that? I have just rounded numbers.
有这样的吗？我刚刚四舍五入的数字。
回答by aioobe
Just do something like
只是做类似的事情
value = value < 0 ? 0 : value;
or
或者
if (value < 0) value = 0;
or
或者
value = Math.max(0, value);
回答by RightSaidFred
I suppose you could use Math.max().
我想你可以使用Math.max().
var num = 90;
num = Math.max(0,num); // 90
var num = -90;
num = Math.max(0,num); // 0
回答by SLaks
If you want to be clever:
如果你想变得聪明：
num = (num + Math.abs(num)) / 2;
However, Math.maxor a conditional operator would be much more understandable.
Also, this has precision issues for large numbers.
但是，Math.max或者条件运算符会更容易理解。
此外，这对于大量数字存在精度问题。
回答by Juan Mendes
Math.positive = function(num) {
return Math.max(0, num);
}
// or
Math.positive = function(num) {
return num < 0 ? 0 : num;
}
回答by Alexandre C.
x < 0 ? 0 : xdoes the job .
x < 0 ? 0 : x做这份工作。
回答by Killy
Remember the negative zero.
记住负零。
function isNegativeFails(n) {
return n < 0;
}
function isNegative(n) {
return ((n = +n) || 1 / n) < 0;
}
isNegativeFails(-0); // false
isNegative(-0); // true
Math.max(-0, 0); // 0
Math.min(-0, 0); // -0
Source: http://cwestblog.com/2014/02/25/javascript-testing-for-negative-zero/
资料来源：http: //cwestblog.com/2014/02/25/javascript-testing-for-negative-zero/
回答by jacobangel
I don't believe that such a function exists with the native Math object. You should write a script to fill in the function if you need to use it.
我不相信这样的函数存在于本机 Math 对象中。如果您需要使用它，您应该编写一个脚本来填充该函数。
