当在字符串上下文中使用时,JavaScript将超过21位的整数转换为科学符号。我打印了一个整数作为URL的一部分。我怎样才能阻止这种转变的发生?


当前回答

试试这个:

Number.standardizenumber = function (number,n) {

  var mantissa = number.toLocaleString(
    'en-US', {
      useGrouping: false,
      signDisplay: "never",
      notation: "scientific",
      minimumFractionDigits: 16,
      maximumFractionDigits: 16
    }
  ).toLowerCase().split('e')[0].replace(/\./g,'');
  var exponentNegative = "0".repeat(Math.max(+Math.abs(number).toExponential().toLowerCase().split('e-')[1]-1,0)) + mantissa;
  var exponentPositive = Math.abs(number)<1E17?mantissa.slice(0,+Math.abs(number).toExponential().toLowerCase().split('e+')[1]+1):mantissa+(Math.abs(number).toExponential().toLowerCase().split('e+')[1]-16);
  var decimalExpPositive = Math.abs(number)<1E17?mantissa.slice(0,Math.abs(number).toExponential().toLowerCase().split('e+')[0]-16):undefined;
  var fullDec = number===0?(1/number<0?'-0':'0'):(1/Math.sign(number)<0?'-':'')+(Math.abs(number)>=1?[exponentPositive,(number%1===0?(decimalExpPositive.slice(+Math.abs(number).toExponential().toLowerCase().split('e+')[1]+1)): undefined)].join('.'):`.${exponentNegative}`);
  return isNaN(number)===false&&Math.abs(number)<1E17?((number%1===0?number.toLocaleString('en-US', {useGrouping: false}):fullDec).includes('.')===false?fullDec.split('.')[0].replace(/\B(?=(\d{3})+(?!\d))/g, ","):fullDec.replace(/(\.[0-9]*[1-9])0+$|\.0*$/,'$1').replace(/\B(?<!\.\d*)(?=(\d{3})+(?!\d))/g, ",")):number.toLocaleString('en-US');
  
}

Number.standardizenumber(.0000001) // .0000001
Number.standardizenumber(1E21) // 1,000,000,000,000,000,000,000
Number.standardizenumber(1_234_567_890.123456) // 1,234,567,890.123456

其他回答

有号码。固定,但如果数字>= 1e21,它使用科学计数法,最大精度为20。除此之外,你可以自己卷,但会很乱。

function toFixed(x) {
  if (Math.abs(x) < 1.0) {
    var e = parseInt(x.toString().split('e-')[1]);
    if (e) {
        x *= Math.pow(10,e-1);
        x = '0.' + (new Array(e)).join('0') + x.toString().substring(2);
    }
  } else {
    var e = parseInt(x.toString().split('+')[1]);
    if (e > 20) {
        e -= 20;
        x /= Math.pow(10,e);
        x += (new Array(e+1)).join('0');
    }
  }
  return x;
}

上面使用了廉价-'n'-easy字符串重复((new Array(n+1)).join(str))。你可以用俄国农民乘法来定义String.prototype.repeat。

这个答案应该只适用于问题的上下文:显示一个大数字而不使用科学计数法。对于其他任何东西,您应该使用BigInt库,例如BigNumber、lemon 's BigInt或BigInteger。展望未来,新的原生BigInt(注意:不是lemon的)应该可用;Chromium和基于它的浏览器(Chrome、新的Edge [v79+]、Brave)和Firefox都支持;Safari的支持正在进行中。

BigInt(n).toString()

例子:

Const n = 13523563246234613317632; console.log("toFixed (wrong): " + n.toFixed()); console.log("BigInt(右):" + BigInt(n).toString());

Beware, though, that any integer you output as a JavaScript number (not a BigInt) that's more than 15-16 digits (specifically, greater than Number.MAX_SAFE_INTEGER + 1 [9,007,199,254,740,992]) may be be rounded, because JavaScript's number type (IEEE-754 double-precision floating point) can't precisely hold all integers beyond that point. As of Number.MAX_SAFE_INTEGER + 1 it's working in multiples of 2, so it can't hold odd numbers anymore (and similiarly, at 18,014,398,509,481,984 it starts working in multiples of 4, then 8, then 16, ...).

因此,如果你可以依赖BigInt支持,输出你的数字作为一个字符串传递给BigInt函数:

const n = BigInt("YourNumberHere");

例子:

const n1 = BigInt(18014398509481985);//错误,将四舍五入到18014398509481984 在' BigInt '看到它之前 console.log(n1.toString() + " <== error "); const n2 = BigInt("18014398509481985");//右,BigInt处理它 console.log(n2.toString() + " <== Right");

目前还没有原生的功能来消解科学记数法。但是,出于这个目的,您必须编写自己的功能。

这是我的:

function dissolveExponentialNotation(number)
{
    if(!Number.isFinite(number)) { return undefined; }

    let text = number.toString();
    let items = text.split('e');

    if(items.length == 1) { return text; }

    let significandText = items[0];
    let exponent = parseInt(items[1]);

    let characters = Array.from(significandText);
    let minus = characters[0] == '-';
    if(minus) { characters.splice(0, 1); }
    let indexDot = characters.reduce((accumulator, character, index) =>
    {
        if(!accumulator.found) { if(character == '.') { accumulator.found = true; } else { accumulator.index++; } }
        return accumulator;
    }, { index: 0, found: false }).index;

    characters.splice(indexDot, 1);

    indexDot += exponent;

    if(indexDot >= 0 && indexDot < characters.length - 1)
    {
        characters.splice(indexDot, 0, '.');
    }
    else if(indexDot < 0)
    {
        characters.unshift("0.", "0".repeat(-indexDot));
    }
    else
    {
        characters.push("0".repeat(indexDot - characters.length));
    }

    return (minus ? "-" : "") + characters.join("");
}

我知道这是很多年后的事情了,但我最近一直在研究一个类似的问题,我想把我的解决方案发布出来。目前接受的答案是用0填充指数部分,我试图找到确切的答案,尽管由于JS在浮点精度方面的限制,通常它对于非常大的数字不是完全准确的。

这确实适用于数学。Pow(2,100),返回正确的值1267650600228229401496703205376。

function toFixed(x) { var result = ''; var xStr = x.toString(10); var digitCount = xStr.indexOf('e') === -1 ? xStr.length : (parseInt(xStr.substr(xStr.indexOf('e') + 1)) + 1); for (var i = 1; i <= digitCount; i++) { var mod = (x % Math.pow(10, i)).toString(10); var exponent = (mod.indexOf('e') === -1) ? 0 : parseInt(mod.substr(mod.indexOf('e')+1)); if ((exponent === 0 && mod.length !== i) || (exponent > 0 && exponent !== i-1)) { result = '0' + result; } else { result = mod.charAt(0) + result; } } return result; } console.log(toFixed(Math.pow(2,100))); // 1267650600228229401496703205376

你的问题:

number :0x68656c6c6f206f72656f
display:4.9299704811152646e+23

你可以使用这个:https://github.com/MikeMcl/bignumber.js

用于任意精度的十进制和非十进制算术的JavaScript库。

是这样的:

let ten =new BigNumber('0x68656c6c6f206f72656f',16);
console.log(ten.toString(10));
display:492997048111526447310191

我想可能有几个类似的答案,但我想到了一个

// If you're gonna tell me not to use 'with' I understand, just,
// it has no other purpose, ;( andthe code actually looks neater
// 'with' it but I will edit the answer if anyone insists
var commas = false;

function digit(number1, index1, base1) {
    with (Math) {
        return floor(number1/pow(base1, index1))%base1;
    }
}

function digits(number1, base1) {
    with (Math) {
        o = "";
        l = floor(log10(number1)/log10(base1));
        for (var index1 = 0; index1 < l+1; index1++) {
            o = digit(number1, index1, base1) + o;
            if (commas && i%3==2 && i<l) {
                o = "," + o;
            }
        }
        return o;
    }
}

// Test - this is the limit of accurate digits I think
console.log(1234567890123450);

注意:这只与javascript数学函数一样准确,并且在for循环之前的行上使用log而不是log10时存在问题;它会把1000以10为底数写成10000,所以我把它改成了log10,因为大多数人都会用10为底数。

这可能不是一个非常准确的解决方案,但我很自豪地说,它可以成功地跨基数转换数字,并提供了一个逗号选项!