我有一个这样的数组:
var arr1 = ["a", "b", "c", "d"];
我如何随机化/打乱它?
我有一个这样的数组:
var arr1 = ["a", "b", "c", "d"];
我如何随机化/打乱它?
当前回答
Array.prototype.shuffle=function(){
var len = this.length,temp,i
while(len){
i=Math.random()*len-- |0;
temp=this[len],this[len]=this[i],this[i]=temp;
}
return this;
}
其他回答
为了更灵活,可以添加另一个参数。在这种情况下,可以从数组中获取一个随机数组,并指定新数组的长度:
function shuffle(array, len = array.length) {
for (let i = array.length - 1; i > 0; i--) {
let j = Math.floor(Math.random() * (i + 1));
[array[i], array[j]] = [array[j], array[i]];
}
return array.slice(0, len);
}
//doesn change array
Array.prototype.shuffle = function () {
let res = [];
let copy = [...this];
while (copy.length > 0) {
let index = Math.floor(Math.random() * copy.length);
res.push(copy[index]);
copy.splice(index, 1);
}
return res;
};
let a=[1, 2, 3, 4, 5, 6, 7, 8, 9];
console.log(a.shuffle());
你可以使用lodash洗牌。就像一个魅力
import _ from lodash;
let numeric_array = [2, 4, 6, 9, 10];
let string_array = ['Car', 'Bus', 'Truck', 'Motorcycle', 'Bicycle', 'Person']
let shuffled_num_array = _.shuffle(numeric_array);
let shuffled_string_array = _.shuffle(string_array);
console.log(shuffled_num_array, shuffled_string_array)
const arr = [
{ index: 0, value: "0" },
{ index: 1, value: "1" },
{ index: 2, value: "2" },
{ index: 3, value: "3" },
];
let shuffle = (arr) => {
let set = new Set();
while (set.size != arr.length) {
let rand = Math.floor(Math.random() * arr.length);
set.add(arr[rand]);
}
console.log(set);
};
shuffle(arr);
对CoolAJ86答案的简单修改,不修改原始数组:
/**
* Returns a new array whose contents are a shuffled copy of the original array.
* @param {Array} The items to shuffle.
* https://stackoverflow.com/a/2450976/1673761
* https://stackoverflow.com/a/44071316/1673761
*/
const shuffle = (array) => {
let currentIndex = array.length;
let temporaryValue;
let randomIndex;
const newArray = array.slice();
// While there remains elements to shuffle...
while (currentIndex) {
randomIndex = Math.floor(Math.random() * currentIndex);
currentIndex -= 1;
// Swap it with the current element.
temporaryValue = newArray[currentIndex];
newArray[currentIndex] = newArray[randomIndex];
newArray[randomIndex] = temporaryValue;
}
return newArray;
};