从数组中采样随机子集

我建议使用Fisher-Yates混洗混洗数组的副本并进行切片：

function getRandomSubarray(arr, size) {    var shuffled = arr.slice(0), i = arr.length, temp, index;    while (i--) {        index = Math.floor((i + 1) * Math.random());        temp = shuffled[index];        shuffled[index] = shuffled[i];        shuffled[i] = temp;    }    return shuffled.slice(0, size);}var x = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];var fiveRandomMembers = getRandomSubarray(x, 5);

请注意，这不是获取大型数组的随机小子集的最有效方法，因为它会不必要地对整个数组进行洗牌。为了获得更好的性能，您可以执行部分​​改组：

function getRandomSubarray(arr, size) {    var shuffled = arr.slice(0), i = arr.length, min = i - size, temp, index;    while (i-- > min) {        index = Math.floor((i + 1) * Math.random());        temp = shuffled[index];        shuffled[index] = shuffled[i];        shuffled[i] = temp;    }    return shuffled.slice(min);}