var compare = array1.length > array2.length ? array1 : array2;
var compareWith = array1.length > array2.length ? array2 : array1;
var uniqueValues = compareWith.filter(function(value){
                    if(compare.indexOf(vakye) == -1)
                       return true;
                   });

这将检查数组中哪个更大，然后进行比较。

我想要一个类似的函数，它接受一个旧数组和一个新数组，并给我一个添加项的数组和一个删除项的数组，我希望它是有效的(所以没有.contains!)。

你可以在这里尝试我提出的解决方案:http://jsbin.com/osewu3/12。

有人能看出算法的问题或改进吗?谢谢!

代码清单:

function diff(o, n) {
  // deal with empty lists
  if (o == undefined) o = [];
  if (n == undefined) n = [];

  // sort both arrays (or this won't work)
  o.sort(); n.sort();

  // don't compare if either list is empty
  if (o.length == 0 || n.length == 0) return {added: n, removed: o};

  // declare temporary variables
  var op = 0; var np = 0;
  var a = []; var r = [];

  // compare arrays and add to add or remove lists
  while (op < o.length && np < n.length) {
      if (o[op] < n[np]) {
          // push to diff?
          r.push(o[op]);
          op++;
      }
      else if (o[op] > n[np]) {
          // push to diff?
          a.push(n[np]);
          np++;
      }
      else {
          op++;np++;
      }
  }

  // add remaining items
  if( np < n.length )
    a = a.concat(n.slice(np, n.length));
  if( op < o.length )
    r = r.concat(o.slice(op, o.length));

  return {added: a, removed: r}; 
}

**这将根据'type'参数为任意2个数组返回一个唯一值数组，或一个重复值数组，或一个非重复值数组(difference)。**

let json1 = ['one', 'two']
let json2 = ['one', 'two', 'three', 'four']

function uniq_n_shit (arr1, arr2, type) {

  let concat = arr1.concat(arr2)
  let set = [...new Set(concat)]

  if (!type || type === 'uniq' || type === 'unique') {

    return set

  } else if (type === 'duplicate') {

    concat = arr1.concat(arr2)
    return concat.filter(function (obj, index, self) {
      return index !== self.indexOf(obj)
    })

  } else if (type === 'not_duplicate') {

    let duplicates = concat.filter(function (obj, index, self) {
      return index !== self.indexOf(obj)
    })

    for (let r = 0; r < duplicates.length; r++) {
      let i = set.indexOf(duplicates[r]);
      if(i !== -1) {
        set.splice(i, 1);
      }
    }

    return set

  }
}

console.log(uniq_n_shit(json1, json2, null)) // => [ 'one', 'two', 'three', 'four' ]
console.log(uniq_n_shit(json1, json2, 'uniq')) // => [ 'one', 'two', 'three', 'four' ]
console.log(uniq_n_shit(json1, json2, 'duplicate')) // => [ 'one', 'two' ]
console.log(uniq_n_shit(json1, json2, 'not_duplicate')) // => [ 'three', 'four' ]

这个怎么样:

Array.prototype.contains = function(needle){
  for (var i=0; i<this.length; i++)
    if (this[i] == needle) return true;

  return false;
} 

Array.prototype.diff = function(compare) {
    return this.filter(function(elem) {return !compare.contains(elem);})
}

var a = new Array(1,4,7, 9);
var b = new Array(4, 8, 7);
alert(a.diff(b));

这样你就可以用array1。diff(array2)来得到它们的区别算法的时间复杂度很可怕- O(array1。长度(我相信)

一个衬垫

const unique = (a) => [...new Set(a)]; const uniqueBy = (x,f)=>Object.values(x.reduce((a,b)=>((a[f(b)]=b),a),{})); const intersection = (a, b) => a.filter((v) => b.includes(v)); const diff = (a, b) => a.filter((v) => !b.includes(v)); const symDiff = (a, b) => diff(a, b).concat(diff(b, a)); const union = (a, b) => diff(a, b).concat(b); const a = unique([1, 2, 3, 4, 5, 5]); console.log(a); const b = [4, 5, 6, 7, 8]; console.log(intersection(a, b), diff(a, b), symDiff(a, b), union(a, b)); console.log(uniqueBy( [ { id: 1, name: "abc" }, { id: 2, name: "xyz" }, { id: 1, name: "abc" }, ], (v) => v.id )); const intersectionBy = (a, b, f) => a.filter((v) => b.some((u) => f(v, u))); console.log(intersectionBy( [ { id: 1, name: "abc" }, { id: 2, name: "xyz" }, ], [ { id: 1, name: "abc" }, { id: 3, name: "pqr" }, ], (v, u) => v.id === u.id )); const diffBy = (a, b, f) => a.filter((v) => !b.some((u) => f(v, u))); console.log(diffBy( [ { id: 1, name: "abc" }, { id: 2, name: "xyz" }, ], [ { id: 1, name: "abc" }, { id: 3, name: "pqr" }, ], (v, u) => v.id === u.id ));

打印稿

操场上的链接

const unique = <T>(array: T[]) => [...new Set(array)];


const intersection = <T>(array1: T[], array2: T[]) =>
  array1.filter((v) => array2.includes(v));


const diff = <T>(array1: T[], array2: T[]) =>
  array1.filter((v) => !array2.includes(v));


const symDiff = <T>(array1: T[], array2: T[]) =>
  diff(array1, array2).concat(diff(array2, array1));


const union = <T>(array1: T[], array2: T[]) =>
  diff(array1, array2).concat(array2);


const intersectionBy = <T>(
  array1: T[],
  array2: T[],
  predicate: (array1Value: T, array2Value: T) => boolean
) => array1.filter((v) => array2.some((u) => predicate(v, u)));


const diffBy = <T>(
  array1: T[],
  array2: T[],
  predicate: (array1Value: T, array2Value: T) => boolean
) => array1.filter((v) => !array2.some((u) => predicate(v, u)));


const uniqueBy = <T>(
  array: T[],
  predicate: (v: T, i: number, a: T[]) => string
) =>
  Object.values(
    array.reduce((acc, value, index) => {
      acc[predicate(value, index, array)] = value;
      return acc;
    }, {} as { [key: string]: T })
  );

只是修整字符串以确保....空格不会影响差异

function arr_diff(a1, a2) {
    var a=[], diff=[];
    for(var i=0;i<a1.length;i++)
        a[a1[i]]=true;
    for(var i=0;i<a2.length;i++)
        if(a[a2[i].trim()]) delete a[a2[i].trim()];
    else a[a2[i].trim()]=true;
    for(var k in a)
        diff.push(k);
    return diff;
}