我有两个JavaScript数组:
var array1 = ["Vijendra","Singh"];
var array2 = ["Singh", "Shakya"];
我希望输出为:
var array3 = ["Vijendra","Singh","Shakya"];
输出数组应删除重复的单词。
如何在JavaScript中合并两个数组,以便从每个数组中只获得唯一的项目,其顺序与它们插入原始数组的顺序相同?
我有两个JavaScript数组:
var array1 = ["Vijendra","Singh"];
var array2 = ["Singh", "Shakya"];
我希望输出为:
var array3 = ["Vijendra","Singh","Shakya"];
输出数组应删除重复的单词。
如何在JavaScript中合并两个数组,以便从每个数组中只获得唯一的项目,其顺序与它们插入原始数组的顺序相同?
当前回答
//1.merge two array into one array
var arr1 = [0, 1, 2, 4];
var arr2 = [4, 5, 6];
//for merge array we use "Array.concat"
let combineArray = arr1.concat(arr2); //output
alert(combineArray); //now out put is 0,1,2,4,4,5,6 but 4 reapeat
//2.same thing with "Spread Syntex"
let spreadArray = [...arr1, ...arr2];
alert(spreadArray); //now out put is 0,1,2,4,4,5,6 but 4 reapete
/*
if we need remove duplicate element method use are
1.Using set
2.using .filter
3.using .reduce
*/
其他回答
只需避开嵌套循环(O(n^2))和.indexOf()(+O(n))。
函数合并(a,b){var哈希={};变量i;对于(i=0;i<a.length;i++){hash[a[i]=真;}对于(i=0;i<b.length;i++){hash[b[i]]=真;}return Object.keys(哈希);}var array1=[“Vijendra”,“Singh”];var array2=[“Singh”,“Shakya”];var array3=合并(array1,array2);console.log(array3);
使用Undercore.js或Lo Dash,您可以执行以下操作:
console.log(_.union([1,2,3],[101,2,1,10],[2,1]));<script src=“https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js“></script>
http://underscorejs.org/#union
http://lodash.com/docs#union
为此……这里有一个单行解决方案:
const x = [...new Set([['C', 'B'],['B', 'A']].reduce( (a, e) => a.concat(e), []))].sort()
// ['A', 'B', 'C']
不是特别可读,但它可能会帮助某人:
将初始累加器值设置为空数组的reduce函数应用于空数组。reduce函数使用concat将每个子数组附加到累加器数组上。其结果作为构造函数参数传递,以创建新的Set。排列运算符用于将集合转换为数组。sort()函数应用于新数组。
如果像我一样,您需要支持较旧的浏览器,这适用于IE6+
function es3Merge(a, b) {
var hash = {},
i = (a = a.slice(0)).length,
e;
while (i--) {
hash[a[i]] = 1;
}
for (i = 0; i < b.length; i++) {
hash[e = b[i]] || a.push(e);
}
return a;
};
http://jsperf.com/merge-two-arrays-keeping-only-unique-values/22
我有一个类似的请求,但它具有数组中元素的Id。
这里是我进行重复数据消除的方法。
它简单,易于维护,使用方便。
// Vijendra's Id = Id_0
// Singh's Id = Id_1
// Shakya's Id = Id_2
let item0 = { 'Id': 'Id_0', 'value': 'Vijendra' };
let item1 = { 'Id': 'Id_1', 'value': 'Singh' };
let item2 = { 'Id': 'Id_2', 'value': 'Shakya' };
let array = [];
array = [ item0, item1, item1, item2 ];
let obj = {};
array.forEach(item => {
obj[item.Id] = item;
});
let deduplicatedArray = [];
let deduplicatedArrayOnlyValues = [];
for(let [index, item] of Object.values(obj).entries()){
deduplicatedArray = [ ...deduplicatedArray, item ];
deduplicatedArrayOnlyValues = [ ...deduplicatedArrayOnlyValues , item.value ];
};
console.log( JSON.stringify(array) );
console.log( JSON.stringify(deduplicatedArray) );
console.log( JSON.stringify(deduplicatedArrayOnlyValues ) );
控制台日志
[{"recordId":"Id_0","value":"Vijendra"},{"recordId":"Id_1","value":"Singh"},{"recordId":"Id_1","value":"Singh"},{"recordId":"Id_2","value":"Shakya"}]
[{"recordId":"Id_0","value":"Vijendra"},{"recordId":"Id_1","value":"Singh"},{"recordId":"Id_2","value":"Shakya"}]
["Vijendra","Singh","Shakya"]