我有对象数组,例如:
let array1 = [
{name: '1', image: '1.jpg'},
{name: '2', image: '2.jpg'},
{name: '3', image: '4.jpg'},
{name: '4', image: '5.jpg'},
];
我想从中获取n个随机元素,并找到用于此目的的函数:
function getRandom(arr, n) {
var result = new Array(n),
len = arr.length,
taken = new Array(len);
while (n--) {
var x = Math.floor(Math.random() * len);
result[n] = arr[x in taken ? taken[x] : x];
taken[x] = --len in taken ? taken[len] : len;
}
return result
}
唯一的问题是,当我想拥有n> arr.length时,此方法不起作用。我想弄清楚在这种情况下如何增加元素数量。例如,重复其中已经存在的元素。
我尝试添加条件:
if(n > len) {
arr.push(arr);
console.log(arr);
}
但这对我没有好处,因为元素被作为另一个对象推送,而不是单独检查console.log:
0: {name: "1", image: "1.jpg"}
1: {name: "2", image: "2.jpg"}
2: {name: "3", image: "4.jpg"}
3: {name: "4", image: "5.jpg"}
4: Array(5)
0: {name: "1", image: "1.jpg"}
1: {name: "2", image: "2.jpg"}
2: {name: "3", image: "4.jpg"}
3: {name: "4", image: "5.jpg"}
4: (5) [{…}, {…}, {…}, {…}, Array(5)]
length: 5
我尝试过的其他方法均无效。如果有人能找到解决方法,我将非常感激。
/////////编辑-整个函数getRandom(arr,n):
function getRandom(arr, n) {
var result = new Array(n),
len = arr.length,
taken = new Array(len);
if (n > len)
throw new RangeError("getRandom: more elements taken than available");
while (n--) {
var x = Math.floor(Math.random() * len);
result[n] = arr[x in taken ? taken[x] : x];
taken[x] = --len in taken ? taken[len] : len;
}
if (arr == warmUpAll) {
document.getElementById("warmup").innerHTML = '<span class="exerciseheader">Warm Up - 10 minutes</span>' + "</br>" ;
}
else if (arr == legsAll){
document.getElementById("legsDisplay").innerHTML = '<span class="exerciseheader">Legs</span>' + "</br>";
}
for (let i=0;i<result.length;i+=1) {
let displayname = document.createTextNode(result[i].name);
if (arr == warmUpAll) {
source = './images/warmUp/' + result[i].image;
warmUpSources.push(source);
document.getElementById('warmup').appendChild(displayname);
document.getElementById('warmup').appendChild(document.createElement("br" ));
}
else if (arr == armsAll) {
source = './images/arms/' + result[i].image;
armsSources.push(source);
document.getElementById('armsDisplay').appendChild(displayname);
document.getElementById('armsDisplay').appendChild(document.createElement("br" ));
}
}
}
答案 0 :(得分:0)
当前,您的代码给出了额外括号的语法错误,并删除了该括号,但仅返回1个随机值。它显然没有循环。你可以试试这个
function fillArrayRandomly(array, n) {
let res = [];
while (res.length !== n) {
let randomValue = array[Math.floor(Math.random() * array.length)];
res.push(randomValue);
}
return res;}