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
非常简单的解决方案与JavaScript的过滤器功能:
Var a1 = ['a', 'b']; Var a2 = ['a', 'b', 'c', 'd']; (arr1, arr2) { var newArr = []; var myArr = ar1 .concat(arr2); newArr = myArr.filter(函数(项){ return arr2.indexOf(item) < 0 || arr1.indexOf(item) < 0; }); 警报(newArr); } diffArray (a1, a2);
其他回答
下面是一个稍微修改的版本,它使用Object来存储哈希,可以处理数组中的数字和字符串。
function arrDiff(a, b) {
const hash = {};
a.forEach(n => { hash[n] = n; });
b.forEach(n => {
if (hash[n]) {
delete hash[n];
} else {
hash[n] = n;
}
});
return Object.values(hash);
}
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"}]
为了获得对称差异,您需要以两种方式比较数组(或在多个数组的情况下以所有方式比较)
ES7 (ECMAScript 2016)
// diff between just two arrays:
function arrayDiff(a, b) {
return [
...a.filter(x => !b.includes(x)),
...b.filter(x => !a.includes(x))
];
}
// diff between multiple arrays:
function arrayDiff(...arrays) {
return [].concat(...arrays.map( (arr, i) => {
const others = arrays.slice(0);
others.splice(i, 1);
const unique = [...new Set([].concat(...others))];
return arr.filter(x => !unique.includes(x));
}));
}
ES6(2015年ECMAScript)
// diff between just two arrays:
function arrayDiff(a, b) {
return [
...a.filter(x => b.indexOf(x) === -1),
...b.filter(x => a.indexOf(x) === -1)
];
}
// diff between multiple arrays:
function arrayDiff(...arrays) {
return [].concat(...arrays.map( (arr, i) => {
const others = arrays.slice(0);
others.splice(i, 1);
const unique = [...new Set([].concat(...others))];
return arr.filter(x => unique.indexOf(x) === -1);
}));
}
ES5 (ECMAScript 5.1)
// diff between just two arrays:
function arrayDiff(a, b) {
var arrays = Array.prototype.slice.call(arguments);
var diff = [];
arrays.forEach(function(arr, i) {
var other = i === 1 ? a : b;
arr.forEach(function(x) {
if (other.indexOf(x) === -1) {
diff.push(x);
}
});
})
return diff;
}
// diff between multiple arrays:
function arrayDiff() {
var arrays = Array.prototype.slice.call(arguments);
var diff = [];
arrays.forEach(function(arr, i) {
var others = arrays.slice(0);
others.splice(i, 1);
var otherValues = Array.prototype.concat.apply([], others);
var unique = otherValues.filter(function (x, j) {
return otherValues.indexOf(x) === j;
});
diff = diff.concat(arr.filter(x => unique.indexOf(x) === -1));
});
return diff;
}
例子:
// diff between two arrays:
const a = ['a', 'd', 'e'];
const b = ['a', 'b', 'c', 'd'];
arrayDiff(a, b); // (3) ["e", "b", "c"]
// diff between multiple arrays
const a = ['b', 'c', 'd', 'e', 'g'];
const b = ['a', 'b'];
const c = ['a', 'e', 'f'];
arrayDiff(a, b, c); // (4) ["c", "d", "g", "f"]
对象数组之间的差异
function arrayDiffByKey(key, ...arrays) {
return [].concat(...arrays.map( (arr, i) => {
const others = arrays.slice(0);
others.splice(i, 1);
const unique = [...new Set([].concat(...others))];
return arr.filter( x =>
!unique.some(y => x[key] === y[key])
);
}));
}
例子:
const a = [{k:1}, {k:2}, {k:3}];
const b = [{k:1}, {k:4}, {k:5}, {k:6}];
const c = [{k:3}, {k:5}, {k:7}];
arrayDiffByKey('k', a, b, c); // (4) [{k:2}, {k:4}, {k:6}, {k:7}]
我同意@luis-sieira的解决方案
我创建了位自解释函数,便于初学者一步一步理解:
function difference(oneArr, twoArr){
var newArr = [];
newArr = oneArr.filter((item)=>{
return !twoArr.includes(item)
});
console.log(newArr)
let arr = twoArr.filter((item)=>{
return !oneArr.includes(item)
});
newArr = newArr.concat(arr);
console.log(newArr)
}
difference([1, 2, 3, 5], [1, 2, 3, 4, 5])
var result = [];
var arr1 = [1,2,3,4];
var arr2 = [2,3];
arr1.forEach(function(el, idx) {
function unEqual(element, index, array) {
var a = el;
return (element!=a);
}
if (arr2.every(unEqual)) {
result.push(el);
};
});
alert(result);