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
使用reduce func查看的另一种方法:
function mergeDistinct(arResult, candidate){
if (-1 == arResult.indexOf(candidate)) {
arResult.push(candidate);
}
return arResult;
}
var array1 = ["Vijendra","Singh"];
var array2 = ["Singh", "Shakya"];
var arMerge = [];
arMerge = array1.reduce(mergeDistinct, arMerge);
arMerge = array2.reduce(mergeDistinct, arMerge);//["Vijendra","Singh","Shakya"];
其他回答
用法:https://gist.github.com/samad-aghaei/7250ffb74ed80732debb1cbb14d2bfb0
var _uniqueMerge = function(opts, _ref){
for(var key in _ref)
if (_ref && _ref[key] && _ref[key].constructor && _ref[key].constructor === Object)
_ref[key] = _uniqueMerge((opts ? opts[key] : null), _ref[key] );
else if(opts && opts.hasOwnProperty(key))
_ref[key] = opts[key];
else _ref[key] = _ref[key][1];
return _ref;
}
Array.prototype.add = function(b){
var a = this.concat(); // clone current object
if(!b.push || !b.length) return a; // if b is not an array, or empty, then return a unchanged
if(!a.length) return b.concat(); // if original is empty, return b
// go through all the elements of b
for(var i = 0; i < b.length; i++){
// if b's value is not in a, then add it
if(a.indexOf(b[i]) == -1) a.push(b[i]);
}
return a;
}
// Example:
console.log([1,2,3].add([3, 4, 5])); // will output [1, 2, 3, 4, 5]
为什么不使用对象?看起来你在尝试建立一套模型。然而,这并不能维持秩序。
var set1 = {"Vijendra":true, "Singh":true}
var set2 = {"Singh":true, "Shakya":true}
// Merge second object into first
function merge(set1, set2){
for (var key in set2){
if (set2.hasOwnProperty(key))
set1[key] = set2[key]
}
return set1
}
merge(set1, set2)
// Create set from array
function setify(array){
var result = {}
for (var item in array){
if (array.hasOwnProperty(item))
result[array[item]] = true
}
return result
}
对于大型输入,更好的选择是对数组进行排序。然后合并它们。
function sortFunction(a, b) {
return a - b;
}
arr1.sort(sortFunction);
arr2.sort(sortFunction);
function mergeDedup(arr1, arr2) {
var i = 0, j = 0, result = [];
while (i < arr1.length && j < arr2.length) {
if (arr1[i] < arr2[j]) {
writeIfNotSameAsBefore(result, arr1[i]);
i++;
}
else if (arr1[i] > arr2[j]) {
writeIfNotSameAsBefore(result, arr2[j]);
j++;
}
else {
writeIfNotSameAsBefore(result, arr1[i]);
i++;
j++;
}
}
while (i < arr1.length) {
writeIfNotSameAsBefore(result, arr1[i]);
i++;
}
while (j < arr2.length) {
writeIfNotSameAsBefore(result, arr2[j]);
j++;
}
return result;
}
function writeIfNotSameAsBefore(arr, item) {
if (arr[arr.length - 1] !== item) {
arr[arr.length] = item;
}
return arr.length;
}
排序将采用O(nlogn+mlogm),其中n和m是数组的长度,O(x)用于合并,其中x=Max(n,m);
只是把我的两分钱扔进去。
function mergeStringArrays(a, b){
var hash = {};
var ret = [];
for(var i=0; i < a.length; i++){
var e = a[i];
if (!hash[e]){
hash[e] = true;
ret.push(e);
}
}
for(var i=0; i < b.length; i++){
var e = b[i];
if (!hash[e]){
hash[e] = true;
ret.push(e);
}
}
return ret;
}
这是我经常使用的方法,它使用一个对象作为哈希查找表来执行重复检查。假设哈希值是O(1),那么这将在O(n)中运行,其中n是a.length+b.length。老实说,我不知道浏览器是如何进行哈希的,但它在数千个数据点上表现良好。