是否有一种方法可以在JavaScript中返回两个数组之间的差异?
例如:
var a1 = ['a', 'b'];
var a2 = ['a', 'b', 'c', 'd'];
// need ["c", "d"]
是否有一种方法可以在JavaScript中返回两个数组之间的差异?
例如:
var a1 = ['a', 'b'];
var a2 = ['a', 'b', 'c', 'd'];
// need ["c", "d"]
当前回答
这个答案是2009年写的,所以有点过时了,但是对于理解这个问题还是很有教育意义的。我今天最好的解决办法是
let difference = arr1.filter(x => !arr2.includes(x));
(此处致谢给其他作者)
我假设你比较的是一个普通数组。如果不是,你需要将for循环改为for ..在循环。
函数arr_diff (a1, a2) { Var a = [], diff = []; For (var I = 0;I < a1.length;我+ +){ A [a1[i]] = true; } For (var I = 0;I < a2.length;我+ +){ If (a[a2[i]]) { 删除一个[a2[我]]; }其他{ A [a2[i]] = true; } } 对于(var k in a) { diff.push (k); } 返回差异; } console.log (arr_diff ([a, b], [a, b, c, d '))); console.log (arr_diff(“abcd”、"中的")); console.log (arr_diff(“必杀技”,“必杀技”));
其他回答
以上Joshaven Potter的回答非常棒。但是它返回数组B中不在数组C中的元素,而不是反过来。例如,如果var a=[1,2,3,4,5,6]。diff([3、4、5、7]);然后它将输出:==>[1,2,6],而不是[1,2,6,7],这是两者之间的实际差异。你仍然可以使用上面的Potter代码,但也可以简单地向后做一次比较:
Array.prototype.diff = function(a) {
return this.filter(function(i) {return !(a.indexOf(i) > -1);});
};
////////////////////
// Examples
////////////////////
var a=[1,2,3,4,5,6].diff( [3,4,5,7]);
var b=[3,4,5,7].diff([1,2,3,4,5,6]);
var c=a.concat(b);
console.log(c);
这应该输出:[1,2,6,7]
类似于Ian Grainger的解决方案(但在打字稿中):
function findDiffs(arrayOne: string[], arrayTwo: string[]) {
let onlyInArrayOne = []
let onlyInArrayTwo = []
let share = []
let [arrayOneCopy, arrayTwoCopy] = [[...arrayOne], [...arrayTwo]]
arrayOneCopy.sort(); arrayTwoCopy.sort()
while (arrayOneCopy.length !== 0 && arrayTwoCopy.length !== 0) {
if (arrayOneCopy[0] == arrayTwoCopy[0]) {
share.push(arrayOneCopy[0])
arrayOneCopy.splice(0, 1)
arrayTwoCopy.splice(0, 1)
}
if (arrayOneCopy[0] < arrayTwoCopy[0]) {
onlyInArrayOne.push(arrayOneCopy[0])
arrayOneCopy.splice(0, 1)
}
if (arrayOneCopy[0] > arrayTwoCopy[0]) {
onlyInArrayTwo.push(arrayTwoCopy[0])
arrayTwoCopy.splice(0, 1)
}
}
onlyInArrayTwo = onlyInArrayTwo.concat(arrayTwoCopy)
onlyInArrayOne = onlyInArrayOne.concat(arrayOneCopy)
return {
onlyInArrayOne,
onlyInArrayTwo,
share,
diff: onlyInArrayOne.concat(onlyInArrayTwo)
}
}
// arrayOne: [ 'a', 'b', 'c', 'm', 'y' ]
// arrayTwo: [ 'c', 'b', 'f', 'h' ]
//
// Results:
// {
// onlyInArrayOne: [ 'a', 'm', 'y' ],
// onlyInArrayTwo: [ 'f', 'h' ],
// share: [ 'b', 'c' ],
// diff: [ 'a', 'm', 'y', 'f', 'h' ]
// }
数据:
var new_storage = JSON.parse('[{"id_order":"0003"},{"id_order":"0004"},{"id_order":"0006"}]');
var old_storage = JSON.parse('[{"id_order":"0001"},{"id_order":"0002"},{"id_order":"0003"},{"id_order":"0004"},{"id_order":"0005"}]');
使用过滤器:
var diff = new_storage
.filter(x => {if(!(old_storage.filter(y => y.id_order==x.id_order)).length){return x}})
.concat(old_storage
.filter(x => {if(!(new_storage.filter(y => y.id_order==x.id_order)).length){return x}})
)
console.log(JSON.stringify(diff))
两个数组的结果不同
[{"id_order":"0006"},{"id_order":"0001"},{"id_order":"0002"},{"id_order":"0005"}]
以下是我使用的方法:
var newArr = a1.filter(function(elem) {
return a2.indexOf(elem) === -1;
}).concat( a2.filter(function(elem) {
return a1.indexOf(elem) === -1;
}));
console.log(newArr);
或者这个
var newArr = a1.concat(a2);
function check(item) {
if (a1.indexOf(item) === -1 || a2.indexOf(item) === -1) {
return item;
}
}
return newArr.filter(check);
如果你有两个对象列表
const people = [{name: 'cesar', age: 23}]
const morePeople = [{name: 'cesar', age: 23}, {name: 'kevin', age: 26}, {name: 'pedro', age: 25}]
let result2 = morePeople.filter(person => people.every(person2 => !person2.name.includes(person.name)))