我见过使用加号运算符将字符串转换为数字的代码。
这看起来像:
var x ="5",y;
y = +x;
console.log(typeof y) //number
这是如何工作的？
最佳答案
事实上，有两个 + 运算符:二元 + 运算符和这个:一元 + 运算符。
看看它是如何描述的in the MDN :
- (Unary Plus)
The unary plus operator precedes its operand and evaluates to its operand but attempts to converts it into a number, if it isn't already. For example, y = +x takes the value of x and assigns that to y; that is, if x were 3, y would get the value 3 and x would retain the value 3; but if x were the string "3", y would also get the value 3. Although unary negation (-) also can convert non-numbers, unary plus is the fastest and preferred way of converting something into a number, because it does not perform any other operations on the number. It can convert string representations of integers and floats, as well as the non-string values true, false, and null. Integers in both decimal and hexadecimal ("0x"-prefixed) formats are supported. Negative numbers are supported (though not for hex). If it cannot parse a particular value, it will evaluate to NaN.
关于javascript - 使用 + 作为转换机制是如何工作的？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19296684/