javascript - 如何产生具有 2 个整数的浮点数？

Question

var ratings = 3193;
var reviews = 9;

var average = parseFloat(ratings) / reviews;  //I want a floating point number at the end.

这是正确的方法吗？

Answer 1

All numbers in JavaScript are double-precision 64-bit binary format IEEE 754. There is no need to typecast "integers" into "floats" as you would expect it from C/C++ and other languages. You need parse* only if you handle strings.

See also:

• Number value

  primitive value corresponding to a double-precision 64-bit binary format IEEE 754 value

• parseInt, parseFloat (both take a string as parameter)

Answer 2

转换不是必需的。JavaScript 会自动在类型之间进行转换。并且数字实际上并未在内部表示为整数。无论如何，它们都是浮点数。

因此，最简单的解决方案应该具有预期的效果：

var ratings = 3193;
var reviews = 9;
var average = ratings/reviews;

您在示例中所拥有的内容会导致引擎转换ratings为字符串并将该字符串解析为双精度（理论上会导致它必须以开头的值），然后再将其视为计算中的分子。