我想基于一个公共属性找到多个对象数组的公共元素。另外,如果一个元素出现不止一次,我希望结果数组反映它在所有数组中出现的次数。
我尝试了以下方法:
var arr = [
[
{ name: 'kiwi', value: 12 },
{ name: 'apple', value: 5 },
{ name: 'apple', value: 12 },
{ name: 'pizza', value: 33 },
{ name: 'pizza', value: 24 },
{ name: 'fish', value: 5 },
{ name: 'milk', value: 5 },
{ name: 'banana', value: 7 },
{ name: 'orange', value: 11 },
],
[
{ name: 'taco', value: 23 },
{ name: 'pizza', value: 78 },
{ name: 'apple', value: 12 },
{ name: 'pizza', value: 33 },
{ name: 'pizza', value: 24 },
{ name: 'fish', value: 5 },
{ name: 'pie', value: 1 },
{ name: 'cake', value: 3 },
{ name: 'banana', value: 7 },
{ name: 'beef', value: 123 },
{ name: 'lime', value: 72 },
{ name: 'pizza', value: 34 },
],
[
{ name: 'apple', value: 12 },
{ name: 'pizza', value: 33 },
{ name: 'pizza', value: 24 },
{ name: 'pizza', value: 23 },
{ name: 'fish', value: 5 },
{ name: 'banana', value: 7 },
{ name: 'banana', value: 77 },
]
];
function findArraysWithCommonName(arr) {
let arrays = [...arr];
var result = arrays.shift().reduce(function(res, v) {
if (arrays.every(function(a) {
return (a.filter(function(e) {
return e.name === v.name
}).length > 0);
})) res.push(v);
return res;
}, []);
return result;
}
console.log(findArraysWithCommonName(arr))
我得到的结果是:
[
{name: "apple", value: 5},
{name: "apple", value: 12},
{name: "pizza", value: 33},
{name: "pizza", value: 24},
{name: "fish", value: 5},
{name: "banana", value: 7}
]
我希望输出为:
[
{name: "apple", value: 12},
{name: "pizza", value: 33},
{name: "pizza", value: 24},
{name: "fish", value: 5},
{name: "banana", value: 7}
]
要么
[
{name: "apple", value: 5},
{name: "pizza", value: 33},
{name: "pizza", value: 24},
{name: "fish", value: 5},
{name: "banana", value: 7}
]
最佳答案
一种方法是建立一个将对象与其数组中“计数”相关联的映射(即对象在arr
中占的次数)。
这可以通过.reduce()
完成,在该过程中,您通过JSON.stringify(obj)
将每个对象序列化为一个字符串-该字符串是对应对象形状和状态的唯一编码,用作key
来标识此形式的对象映射。 key
用于为arr
中遇到的每个对象查询和更新映射的“计数”值。
构建映射后,请按“计数”值大于1的那些过滤映射项。
最后,对于任何过滤的条目,通过.map()
反序列化这些条目的相应键,以获得对象数组,该对象数组在原始arr
中占据的空间大于一个。
这种方法可以实现为:
var arr=[[{name:'kiwi',value:12},{name:'apple',value:5},{name:'apple',value:12},{name:'pizza',value:33},{name:'pizza',value:24},{name:'fish',value:5},{name:'milk',value:5},{name:'banana',value:7},{name:'orange',value:11}],[{name:'taco',value:23},{name:'pizza',value:78},{name:'apple',value:12},{name:'pizza',value:33},{name:'pizza',value:24},{name:'fish',value:5},{name:'pie',value:1},{name:'cake',value:3},{name:'banana',value:7},{name:'beef',value:123},{name:'lime',value:72},{name:'pizza',value:34}],[{name:'apple',value:12},{name:'pizza',value:33},{name:'pizza',value:24},{name:'pizza',value:23},{name:'fish',value:5},{name:'banana',value:7},{name:'banana',value:77}]];
/* Flatten array heirachy */
const flatArr = arr.flat();
/* Obtain a count mapping for each object's occourance in flatArr */
const mapObjectToCount = flatArr.reduce((map, item) => {
const key = JSON.stringify(item);
const count = (map[key] ? map[key] : 0) + 1;
return { ...map, [ key ] : count };
}, {})
/* Get key/value pair of the prior mapping, filter the objects by
those that occour more that one time, and obtain the original object
by parsing the key */
const result = Object.entries(mapObjectToCount)
.filter(([json, count]) => count > 1)
.map(([json]) => JSON.parse(json));
console.log(result)
关于javascript - 基于属性的多个数组的交集,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/57650251/