数字列表到数字列表

Question

我有一个数字列表，格式如下：

[[1,2],[3,4],[5,1]]

我期待得到下一个输出：

[1,2,3,4,5]

这是我当前方法的一个示例：

<!DOCTYPE html>
<html>
<head>
    <title>Expected - [1,2,3,4,5,6,7,8,9,10]</title>
</head>
<body>
    <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
    <script type="text/javascript">
        $(document).ready(function()
        {
            // Expected - [1,2,3,4,5,6,7,8,9,10];
            var array_of_arrays = [[1, 2], [3, 4], [5, 6], [7, 8], [9, 10], [1, 2], [3, 4], [5, 6], [7, 8], [9, 10]];
            console.log(array_of_arrays);

            // Section 1 - code does what I expect. I would like something like Section 2.
            var array_of_values = [];
            array_of_arrays.map((x) => {
                x.map((y) => {
                    if (array_of_values.indexOf(y) == -1)
                        array_of_values.push(y)
                })
            });
            console.log(array_of_values);

            // Section 2 - This code does not do what I expect.
            var resp = array_of_arrays.map(x => x.map(y => y));
            console.log(resp);
        });
    </script>
</body>
</html>

Answer 1

您可以使用 flatMap 来做到这一点。它根据提供的回调函数展平（取消嵌套）数组。使用过滤器过滤掉重复项并使用 sort()

对它们进行排序

var a=[[1,2],[3,4],[5,1]].flatMap((x)=>x);
var arr=[];
console.log(a.filter((e)=>arr.indexOf(e)==-1?arr.push(e):false).sort());

Answer 2

您可以使用 Array.prototype.reduce() and using Set

let arr = [[1,2],[3,4],[5,1]]
//flatting array
arr = arr.reduce((ac,item) => ([...ac,...item]),[])
//remove dupliactes
arr = [...new Set(arr)];
console.log(arr);

Answer 3

一种方法可以使用 reduce() with a set 作为 accumulator:

let input = [[1,2],[3,4],[5,1]];

let res = input.reduce((acc, a) =>
{
    a.forEach(x => acc.add(x));
    return acc;
}, new Set());

console.log(Array.from(res));

.as-console {background-color:black !important; color:lime;}
.as-console-wrapper {max-height:100% !important; top:0;}

另一种方法是使用新的 flat() 方法：

let input = [[1,2],[3,4],[5,1]];
let res = new Set(input.flat());
console.log(Array.from(res));

.as-console {background-color:black !important; color:lime;}
.as-console-wrapper {max-height:100% !important; top:0;}

Answer 4

您可以创建一个 distinct 过滤器并使用 flatMap

const distinct = (value, index, self) => {
  return self.indexOf(value) == index;
}

console.log(
  [[1,2],[3,4],[5,6],[7,8],[9,10],[1,2],[3,4],[5,6],[7,8],[9,10]]
  .flatMap(x => x)
  .filter(distinct)
);

Answer 5

这是你想要的吗

阅读评论

var array_of_arrays = [[1, 2],[3, 4], [5, 6], [7, 8], [9, 10], [1, 2],[3, 4], [5, 6], [7, 8], [9, 10]];
// flat the array and then select distinct after that sort the array out
var arr = array_of_arrays.flatMap((x)=>x).filter((x, i, a) => a.indexOf(x) == i).sort((a,b)=> a-b)

console.log(arr)

Answer 6

你可以使用 reduce 并传递 Set 对象作为它的初始值，Set 为唯一值。

 var list = [[1,2],[3,4],[5,1]];
 var arr = list.reduce((acc, c)=>{ c.map((a)=>{  acc.add(a) }); return acc; }, new Set());

数字列表到数字列表

List of numbers to list of numbers

javascript

arrays

jquery

filter

arrow-functions