function isEven(x){
var m = x % 2;
return m <= false
}
[0, 1, 2, 3, 4, 5, 6, 7, 8].forEach(x => console.log(x, isEven(x)));
之所代码>和m == 0。 0＆lt; = true是正确的，因此该功能也返回正确的结果。
!n is a red herring. For any value of x other than 0, !n will be false; it will be true when x == 0.
m is 0 for even numbers, 1 for odd numbers. When you compare a number with a boolean, the boolean is converted to a number. So m <= false is equivalent to m <= 0. This will be true when m is 0.
So you can get rid of n and just use this:
function isEven(x){
var m = x % 2;
return m <= false
}
[0, 1, 2, 3, 4, 5, 6, 7, 8].forEach(x => console.log(x, isEven(x)));
The reason why it works with !n is because in the only case where !n is true, x == 0 and m == 0. 0 <= true is true, so the function returns the correct result then as well.
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如果x为0，则第一个
n将是假的，否则真相。如果论点是偶数而不是0：
如果论点奇怪而积极，则为真实：
参数均匀，而0：
但是当参数奇怪和负面时，代码不起作用，因为负数奇数
％2给出-1，而不是1。MFirst
nwill be falsey if x is 0, and truthy otherwise.If the argument is even and not 0:
If the argument is odd and positive:
If the argument is even and 0:
But the code doesn't work when the argument is odd and negative, because a negative odd number
% 2gives -1, not 1.！n是红鲱鱼。对于x的任何值，0，！n 将为false;当x == 0时，它将是true。m是0偶数1奇数数字。当您将数字与布尔值进行比较时，布尔值将转换为一个数字。因此，m＆lt; = false等效于m＆lt; = 0。当m是0时，这将是正确的。因此，您可以摆脱
n，只需使用以下操作：之所代码>和
m == 0。0＆lt; = true是正确的，因此该功能也返回正确的结果。!nis a red herring. For any value ofxother than0,!nwill befalse; it will betruewhenx == 0.mis0for even numbers,1for odd numbers. When you compare a number with a boolean, the boolean is converted to a number. Som <= falseis equivalent tom <= 0. This will be true whenmis0.So you can get rid of
nand just use this:The reason why it works with
!nis because in the only case where!nistrue,x == 0andm == 0.0 <= trueis true, so the function returns the correct result then as well.