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
如果数组不是简单类型,则可以采用上面的答案之一:
Array.prototype.diff = function(a) {
return this.filter(function(i) {return a.map(function(e) { return JSON.stringify(e); }).indexOf(JSON.stringify(i)) < 0;});
};
这种方法适用于复杂对象的数组。
其他回答
function arrayDiff(a, b) {
return a.concat(b).filter(val => !(b.includes(val)));
//(or) return a.concat(b).filter(val => !(a.includes(val) && b.includes(val)));
}
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”));
只是想…为了一个挑战;-)这个工作…(对于字符串,数字等的基本数组)没有嵌套数组
function diffArrays(arr1, arr2, returnUnion){
var ret = [];
var test = {};
var bigArray, smallArray, key;
if(arr1.length >= arr2.length){
bigArray = arr1;
smallArray = arr2;
} else {
bigArray = arr2;
smallArray = arr1;
}
for(var i=0;i<bigArray.length;i++){
key = bigArray[i];
test[key] = true;
}
if(!returnUnion){
//diffing
for(var i=0;i<smallArray.length;i++){
key = smallArray[i];
if(!test[key]){
test[key] = null;
}
}
} else {
//union
for(var i=0;i<smallArray.length;i++){
key = smallArray[i];
if(!test[key]){
test[key] = true;
}
}
}
for(var i in test){
ret.push(i);
}
return ret;
}
array1 = "test1", "test2","test3", "test4", "test7"
array2 = "test1", "test2","test3","test4", "test5", "test6"
diffArray = diffArrays(array1, array2);
//returns ["test5","test6","test7"]
diffArray = diffArrays(array1, array2, true);
//returns ["test1", "test2","test3","test4", "test5", "test6","test7"]
注意排序可能不会像上面提到的那样…但是如果需要的话,可以在数组上调用.sort()对其进行排序。
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);
const difference = function (baseArray, arrayToCampare, callback = (a, b) => a!== b) {
if (!(arrayToCampare instanceof Array)) {
return baseArray;
}
return baseArray.filter(baseEl =>
arrayToCampare.every(compareEl => callback(baseEl, compareEl)));
}