在多个数组中查找交集

Question

我正在尝试在对象内的多个数组中找到相交值，如下所示：

object = {
  filterA: ["1","2","3","4"],
  filterB: ["2","5","6","7"],
  filterN: ["2","4","7"]
}

对象可以包含多个数组，键的名称可以不同。在所描述的对象中，我只需要返回“2”。

我试图建立在这个答案的基础上：但我无法弄明白，因为它使用静态变量 (a,b,c) 作为示例。如果有办法用 lodash 做到这一点，我们将不胜感激，但 ES 5 中的香草 javascript 也可以！

Answer 1

遍历第一个属性值（数组）并通过与剩余的属性值进行比较来过滤掉。

// get property values(arraya as array)
let arr = Object.values(object);


let res = arr[0]
  // iterate over first array
  // check value present in remaining object values(arrays)
  .filter(v => arr.slice(1).every(a => a.includes(v)));

let object = {
  filterA: ["1", "2", "3", "4"],
  filterB: ["2", "5", "6", "7"],
  filterN: ["2", "4", "7"]
};


let arr = Object.values(object);

let res = arr[0].filter(v => arr.slice(1).every(a => a.includes(v)));


console.log(res)

Answer 2

object = {
  filterA: ["1","2","3","4"],
  filterB: ["2","5","6","7"],
  filterN: ["2","4","7"]
}

let arr = Object.values(object);

let res = arr[0].filter(v => arr.slice(1).every(a => a.includes(v)));


console.log(res)

Answer 3

您可以获得这些值并取 Set and filter with Set#has。

var object = { filterA: ["1", "2", "3", "4"], filterB: ["2", "5", "6", "7"], filterN: ["2", "4", "7"] },
    result = Object
        .values(object)
        .reduce((a, b) => b.filter(Set.prototype.has, new Set(a)));

console.log(result);

Answer 4

reduce 会为您完成这项工作。在下面查看我的代码。

var object = {
  filterA: ["1","2","3","4"],
  filterB: ["2","5","6","7"],
  filterN: ["2","4","7"]
}

var res = Object.values(object).reduce(function (acc, array) {
  return _.intersection(acc, array)
})

console.log(res)

<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.11/lodash.min.js"></script>

Answer 5

我有一个简单的单行方法：

const res = Object.values(object).reduce((a, b) => a.filter(i => b.includes(i)))

但由于您希望在 ES5 (ECMAScript 2009) 版本中使用它，这意味着没有箭头函数，没有 includes()，也没有使用 Set 对象。

const res = Object.values(object).reduce(function (a, b) { 
  return a.filter(function(i) {
    //return b.includes(i);
    return b.indexOf(i) >= 0;
  });
});

console.log(res);

Answer 6

Lodash 的 _.intersection() can handle multiple arrays. You can create a function with _.flow() that gets an array of arrays from the object with _.values(), and computes the intersection by using _.intersection() with _.spread()。

const { flow, values, spread, intersection } = _

const fn = flow(
  values, // get the arrays
  spread(_.intersection) // spread into intersection
)

const object = {
  filterA: ["1","2","3","4"],
  filterB: ["2","5","6","7"],
  filterN: ["2","4","7"]
}

const result = fn(object)

console.log(result)

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>

Answer 7

let arrayOfComparisonArrays = [[1,2,3,4,5], [5,3], [1,3,4,5], [5,1,3]]
let intersectionArray

intersectionArray = arrayOfComparisonArrays.reduce((lastArray, nextArray)=>{
    let intersection = lastArray.filter(x => nextArray.includes(x))
    return intersection
})

//intersectionArray: [ 3, 5 ]

在多个数组中查找交集

Finding intersection in multiple arrays

javascript

arrays

intersection

lodash