我有一个包含对象数组的对象。
obj = {};
obj.arr = new Array();
obj.arr.push({place:"here",name:"stuff"});
obj.arr.push({place:"there",name:"morestuff"});
obj.arr.push({place:"there",name:"morestuff"});
我想知道从数组中删除重复对象的最佳方法是什么。例如,obj.arr将变成。。。
{place:"here",name:"stuff"},
{place:"there",name:"morestuff"}
如果您可以使用诸如下划线或lodash之类的Javascript库,我建议查看它们库中的_.uniq函数。来自lodash:
_.uniq(array, [isSorted=false], [callback=_.identity], [thisArg])
基本上,您传入数组,这里是一个对象文本,然后传入要在原始数据数组中删除重复项的属性,如下所示:
var data = [{'name': 'Amir', 'surname': 'Rahnama'}, {'name': 'Amir', 'surname': 'Stevens'}];
var non_duplidated_data = _.uniq(data, 'name');
更新:Lodash现在也引入了.uniqBy。
您也可以使用地图:
const dedupThings = Array.from(things.thing.reduce((m, t) => m.set(t.place, t), new Map()).values());
完整样本:
const things = new Object();
things.thing = new Array();
things.thing.push({place:"here",name:"stuff"});
things.thing.push({place:"there",name:"morestuff"});
things.thing.push({place:"there",name:"morestuff"});
const dedupThings = Array.from(things.thing.reduce((m, t) => m.set(t.place, t), new Map()).values());
console.log(JSON.stringify(dedupThings, null, 4));
结果:
[
{
"place": "here",
"name": "stuff"
},
{
"place": "there",
"name": "morestuff"
}
]
const objectsMap = new Map();
const placesName = [
{ place: "here", name: "stuff" },
{ place: "there", name: "morestuff" },
{ place: "there", name: "morestuff" },
];
placesName.forEach((object) => {
objectsMap.set(object.place, object);
});
console.log(objectsMap);
如果您可以等到所有添加之后再消除重复项,典型的方法是首先对数组进行排序,然后消除重复项。排序避免了在遍历每个元素时扫描数组的N*N方法。
“消除重复项”函数通常称为unique或uniq。一些现有的实现可以结合这两个步骤,例如原型的uniq
如果你的图书馆还没有,这篇文章没有什么想法可以尝试(还有一些需要避免:-)!我个人认为这是最直接的:
function unique(a){
a.sort();
for(var i = 1; i < a.length; ){
if(a[i-1] == a[i]){
a.splice(i, 1);
} else {
i++;
}
}
return a;
}
// Provide your own comparison
function unique(a, compareFunc){
a.sort( compareFunc );
for(var i = 1; i < a.length; ){
if( compareFunc(a[i-1], a[i]) === 0){
a.splice(i, 1);
} else {
i++;
}
}
return a;
}