如何在JavaScript中显示整数？ [英] How do I display whole number in JavaScript?

问题描述

  var product = 50000000 * 39048902222211111111111111111111：
 alert（product） ; //这给了我1.9524451111105555e + 39。 
  

是否有任何方法显示整个数字，而不是 e + 39 东西？

解决方案

您试图表示的整数值大于Javascript可以处理的整数精度（fixed-精确算术）。最大安全整数为 -9007199254740991 至 9007199254740991 或 +/-（2 ^ 53-1 ）

虽然 9007199254740992 可以表示为不安全。为什么？试试 jsFiddle

Javascript

  alert（9007199254740992 + 1）; 
  

输出

  9007199254740992 
  

请参阅 specification ecma-262 / 5.1 /＃sec-8.5

您可以使用库来进行任意精度算术，或自行推出。

使用一个这样的库， bignumber。 js ，使用 require.js

Javascript

  require.config（{ 
 paths：{
 bignumberjs：'https://raw.github.com/MikeMcl/bignumber.js/master/bignumber.min'
} 
}）; 
 
必须（['bignumberjs']，函数（BigNumber）{
 BigNumber.config（{
 EXPONENTIAL_AT：100 
}）; 
 
 var product = new BigNumber（'50000000'）。times（'39048902222211111111111111111111'）; 
 
 alert（product）; 
 
}）; 
  

输出

  1952445111110555555555555555555550000000 
  

关于jsFiddle

Let's say I write this in JS:

var product = 50000000*39048902222211111111111111111111:
alert(product); //this gives me 1.9524451111105555e+39.

Is there any way to display the whole number, and not that e+39 thing?

解决方案

The integer values you are trying to represent are larger than the integer precision that Javascript can handle (fixed-precision arithmetic). Maximum safe integers are -9007199254740991 to 9007199254740991 or +/-(2^53-1)

While 9007199254740992 can be represented it is considered unsafe. Why? Try this jsFiddle

Javascript

alert(9007199254740992 + 1);

Output

9007199254740992

See specification ecma-262/5.1/#sec-8.5

But you can use a library for arbitrary-precision arithmetic, or roll your own.

Using one such library, bignumber.js, loaded using require.js

Javascript

require.config({
    paths: {
        bignumberjs: 'https://raw.github.com/MikeMcl/bignumber.js/master/bignumber.min'
    }
});

require(['bignumberjs'], function (BigNumber) {
    BigNumber.config({
        EXPONENTIAL_AT: 100
    });

    var product = new BigNumber('50000000').times('39048902222211111111111111111111');

    alert(product);

});

Output

1952445111110555555555555555555550000000

On jsFiddle

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