Question

我有这个功能：

Number.random = function(minimum, maximum, precision) {
    minimum = minimum === undefined ? 0 : minimum;
    maximum = maximum === undefined ? 9007199254740992 : maximum;
    precision = precision === undefined ? 0 : precision;

    var random = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;

    return random;
}

目前还没有实现精确度，有没有人对如何实现它有任何好的想法？精度选项的目的是为您提供固定数量的多个小数位，例如：

// A number from 0 to 10 that will always come back with two decimal places
Number.random(0, 10, 2); // 3.14

Answer 1

试试这个：

Number.random = function(minimum, maximum, precision) {
    minimum = minimum === undefined ? 0 : minimum;
    maximum = maximum === undefined ? 9007199254740992 : maximum;
    precision = precision === undefined ? 0 : precision;

    var random = Math.random() * (maximum - minimum) + minimum;

    return random.toFixed(precision);
}

它使用.toFixed()函数来设置精度

演示：http://jsfiddle.net/2rFW8/1/

Answer 2

您可以尝试将数字乘以10^precision，对其进行四舍五入，然后将其除以10^precision。那会给你想要的结果。下面是这个逻辑的粗略实现。您可能希望在precision参数上添加一些错误检查，或者使用其他一些方法来计算（例如Math.pow）。

Number.random = function(minimum, maximum, precision) {
    minimum = minimum === undefined ? 0 : minimum;
    maximum = maximum === undefined ? 9007199254740992 : maximum;
    precision = precision === undefined ? 0 : precision;

    var random = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;

    for (var i = 0; i < precision; i++) {
        random = random * 10;
    }
    random = Math.round(random);
    for (var i = 0; i < precision; i++) {
        random = random / 10;
    }

    return random;
}

Answer 3

     Number.random = function(minimum, maximum, precision) {
     minimum = minimum||0;
     maximum = maximum ||9007199254740992;
    precision =precision ||0;

    var random = Math.random() * (maximum - minimum + 1) + minimum;

    return random.toFixed(precision);
  }

 //call Number.random(0,10.10,3)

Answer 4

试试这个：

Number.random = function(minimum, maximum, precision) {
    minimum = minimum === undefined ? 0 : minimum;
    maximum = maximum === undefined ? 9007199254740992 : maximum;
    precision = precision === undefined ? 0 : precision;

    var random = Math.random() * (maximum - minimum + 1) + minimum;

    return Math.round(random * Math.pow(10, precision)) / Math.pow(10, precision);
}

Answer 5

因为你没有定义任何限制w.r.t.你可能想要的precision，并牢记Javascript中Number的限制（准确的数字表示），那么你可能会发现string表示可以接受。在这种情况下，你可能想要做这样的事情。

的Javascript

var maxInteger = 9007199254740992;

function randomInteger(minimum, maximum) {
    return Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
}

Number.random = function (minimum, maximum, precision) {
    minimum = typeof minimum !== 'number' ? 0 : minimum;
    minimum = minimum < -maxInteger ? -maxInteger : minimum;
    maximum = typeof maximum !== 'number' || maximum > maxInteger ? maxInteger : maximum;
    precision = typeof precision !== 'number' || precision < 0 ? 0 : precision;

    var random = randomInteger(minimum, maximum).toString(),
        decimals;

    if (precision) {
        decimals = '';
        while (decimals.length < precision) {
            decimals += randomInteger(0, maxInteger)
        }

        random += '.' + decimals.slice(0, precision);
    }

    return random;
}

console.log(Number.random(-maxInteger, maxInteger, 40));

在jsFiddle

上

在JavaScript中生成精度随机数

5 个答案: