如何在 lodash 中合并嵌套数组

Question

我有以下数组格式，我想使用 lodash 或普通 js 来合并它。

var testArray = [[1,2,3,4,5,6,7,8],[1,2,3,4,5,10,7,8],[1,2,3,6,7,8],[9],[3,4,5]]

我想将所有这些合并为一个，输出应低于数组。

testArray  = [1,2,3,4,5,6,7,8,9,10]

Answer 1

您可以将flattenDeep 与_.union 结合使用。如果需要，应用排序

var testArray = [[1,2,3,4,5,6,7,8],[1,2,3,4,5,10,7,8],[1,2,3,6,7,8],[9],[3,4,5]],
    result = _.chain(testArray)
             .flattenDeep()
             .union();

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.15.0/lodash.min.js"></script>

Answer 2

将_.union() 应用于父数组：

var testArray = [[1,2,3,4,5,6,7,8],[1,2,3,4,5,10,7,8],[1,2,3,6,7,8],[9],[3,4,5]];

var result = _.union.apply(_, testArray);

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.2/lodash.min.js"></script>

如果支持 ES6，则使用 array spread：

const testArray = [[1,2,3,4,5,6,7,8],[1,2,3,4,5,10,7,8],[1,2,3,6,7,8],[9],[3,4,5]];

const result = _.union(...testArray);

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.2/lodash.min.js"></script>

Answer 3

在 ES6 中，您可以使用扩展语法 ... 和 Set 来做到这一点

var testArray = [[1,2,3,4,5,6,7,8],[1,2,3,4,5,10,7,8],[1,2,3,6,7,8],[9],[3,4,5]]

var result = [...new Set([].concat(...testArray))];
console.log(result)

Answer 4

您可以拨打_.union.apply(null, arrays)。它记录在这里：

https://lodash.com/docs/#union

> var testArray = [[1,2,3,4,5,6,7,8],[1,2,3,4,5,10,7,8],[1,2,3,6,7,8],[9],[3,4,5]]
> lodash.union.apply(null, testArray)
[ 1, 2, 3, 4, 5, 6, 7, 8, 10, 9 ]

应用技巧是将数组数组转换为函数调用参数。如果您还需要对其进行排序，您可以在其末尾添加.sort()。

Answer 5

如果你需要，只在 ES5 中：

var flattened = Object.keys(testArray.reduce(function(acc, cur) {
  cur.forEach(function(v) {acc[v] = true;});
  return acc;
}, {})).sort(function(a, b) {return a - b;});