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

最简单的方法是使用concat()合并数组,然后使用filter()删除重复项,或者使用concat()将合并的数组放入Set()中。

第一种方式:

const firstArray = [1,2, 2];
const secondArray = [3,4];
// now lets merge them
const mergedArray = firstArray.concat(secondArray); // [1,2,2,3,4]
//now use filter to remove dups
const removeDuplicates = mergedArray.filter((elem, index) =>  mergedArray.indexOf(elem) === index); // [1,2,3, 4]

第二种方式(但对UI有性能影响):

const firstArray = [1,2, 2];
const secondArray = [3,4];
// now lets merge them
const mergedArray = firstArray.concat(secondArray); // [1,2,2,3,4]
const removeDuplicates = new Set(mergedArray);

其他回答

假设原始阵列不需要重复数据消除,这应该非常快,保持原始顺序,并且不会修改原始阵列。。。

function arrayMerge(base, addendum){
    var out = [].concat(base);
    for(var i=0,len=addendum.length;i<len;i++){
        if(base.indexOf(addendum[i])<0){
            out.push(addendum[i]);
        }
    }
    return out;
}

用法:

var array1 = ["Vijendra","Singh"];
var array2 = ["Singh", "Shakya"];
var array3 = arrayMerge(array1, array2);

console.log(array3);
//-> [ 'Vijendra', 'Singh', 'Shakya' ]

给定两个没有重复的简单类型的排序数组,这将在O(n)时间内合并它们,并且输出也将被排序。

function merge(a, b) {
    let i=0;
    let j=0;
    let c = [];
    for (;;) {
        if (i == a.length) {
            if (j == b.length) return c;
            c.push(b[j++]);
        } else if (j == b.length || a[i] < b[j]) {
            c.push(a[i++]);
        } else {
            if (a[i] == b[j]) ++i;   // skip duplicates
            c.push(b[j++]);
        }
    }
}

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

合并两个阵列有很多解决方案。它们可以分为两大类(除了使用lodash或underline.js等第三方库)。

a) 组合两个数组并删除重复项。

b) 在组合项目之前过滤掉它们。

合并两个数组并删除重复项

结合

// mutable operation(array1 is the combined array)
array1.push(...array2);
array1.unshift(...array2);

// immutable operation
const combined = array1.concat(array2);
const combined = [...array1, ...array2];    // ES6

统一

统一数组有很多方法,我个人建议使用以下两种方法。

// a little bit tricky
const merged = combined.filter((item, index) => combined.indexOf(item) === index);
const merged = [...new Set(combined)];

在组合项目之前筛选出项目

还有很多方法,但我个人建议使用以下代码,因为它简单。

const merged = array1.concat(array2.filter(secItem => !array1.includes(secItem)));
//Array.indexOf was introduced in javascript 1.6 (ECMA-262) 
//We need to implement it explicitly for other browsers, 
if (!Array.prototype.indexOf)
{
  Array.prototype.indexOf = function(elt, from)
  {
    var len = this.length >>> 0;

    for (; from < len; from++)
    {
      if (from in this &&
          this[from] === elt)
        return from;
    }
    return -1;
  };
}
//now, on to the problem

var array1 = ["Vijendra","Singh"];
var array2 = ["Singh", "Shakya"];

var merged = array1.concat(array2);
var t;
for(i = 0; i < merged.length; i++)
  if((t = merged.indexOf(i + 1, merged[i])) != -1)
  {
    merged.splice(t, 1);
    i--;//in case of multiple occurrences
  }

其他浏览器的indexOf方法的实现取自MDC