JS数组去重 ES6 方法

Posted 2020-12-27 小猴子会上树

let arr = [0, 0, 0, 0, 1, 2, 3, 4, 4, 5, 2, 3, 3, 3, 9, 8, 9];

//数组去重法1

console.log(Array.from(new Set(arr)));

//数组去重法2

console.log(...new Set(arr));

//数组去重法3

let newarr = [];

for (var i = 0; i < arr.length; i++) {

if (newarr.indexOf(arr[i]) == -1) {

newarr.push(arr[i]);

};

};

console.log(newarr);

//数组去重法4

let newarr2 = [];

arr.sort(); //先将数组排序

// newarr2.push(arr[0]);

for (var i = 0; i < arr.length; i++) {

if (arr[i] !== arr[i + 1]) { //判断后一项 是否跟前一项一样 将后一项放入新数组

newarr2.push(arr[i]);

};

};

console.log(newarr2);

//数组去重 法5

var res = [arr[0]];

for (var i = 0; i < arr.length; i++) {

var repeat = false;

// console.log(res);

for (var j = 0; j < res.length; j++) {

if (arr[i] == res[j]) {

repeat = true;

break;

}

}

if (!repeat) {

res.push(arr[i]);

}

}

console.log(res);

//数组去重 法6

var res = [];

var json = {};

for (var i = 0; i < arr.length; i++) {

if (!json[arr[i]]) {

res.push(arr[i]);

json[arr[i]] = 1;

}

}

console.log(res);