我想用给定次数的扩展语法填充数组 [ ]

Question

所以我有一个可变大小的变量，它计算一个参数中传递了多少个数组。

concatenate(...arg){
 let size = arg.length ;
}

我想使用与该大小相等的次数的扩展语法，更具体地说我想连接所有数组，例如：

let arr1 = [1,2,3];
let arr2 = [3,2,1];
let arr3 = [4,5,6];
// unknown number of array

let finalArr = [...arr1,...arr2,...arr3,...etc];

所以我想问你的是用一个可以为我处理的模板替换硬编码的 finalArr？

到目前为止我尝试了什么：

// Arrays share the same content,ex : Arr : {content:[Arr(3)}
function concatenate(...arg){
 let size = arg.length;
 let arrays = arg;
 let tmplt = Arr(size+1).join(`Arr${size}`);
 let finalArr = [];
 while(size>=0){
  finalArr= [tmplt];
  size--;
}
return finalArr;
}

//input
let var1 = [{content:[2,9,10]}];
let var2 = [{content:[3,1,3]}];
let var3 = [{content:[9,1,8]}];
var1.concatenate(var2,var3);

// expected output
[2,9,10,3,1,3,9,1,8]

最后，我尝试在我制作的 class 列表中重现 Array 的 concat() 方法。规则是：不允许使用 Array.prototype.methods()。到目前为止的完整代码：

 class List {
  constructor(items){
   this.content = !items ? [] : items;
   this.size = this.length();
 }
 length(arg=0){
  let size = arg;
  if(!this.content[arg]){
   return size;
 }
  size++;
 return this.length(size);
 }
 append(arg){
  if(this.size ==0 && this.size == arg.size){
   this.content = new List();
   return this.content;
 }
 this.content = [...this.content,...arg.content] 
 return this.content;
 }
 concatenate(...arg){ 
  let test = arg;
  let size = 0;
  let final = [];
  while(test[size]!=undefined){
  // final += [...test[size].content];
  size++;
  let x = Array(size+1).join(`...test${size}.content`);
  while(size>=0){
    size--;
   
     }
    }

   }

  }

  let aList = new List([2,9,10]);

  let anotherList = new List([3,14,1]);

  let thirdList = new List([9,0,8]);

  aList.concatenate(anotherList,thirdList);

Answer 1

您可以使用 a generator function which takes arrays delegates to each of the iterators。这允许您根据需要展平任意数量的数组，并且可以与扩展符号一起使用：

function* concat(...arrays) {
  for (const array of arrays)
    yield* array;
}

function concatenate(...arg){
 return [...concat(...arg)];
}


let arr1 = [1,2,3];
let arr2 = [3,2,1];
let arr3 = [4,5,6];

let finalArr = concatenate(arr1, arr2, arr3);

console.log(finalArr);

.as-console-wrapper { max-height: 100% !important; }

Answer 2

您可以使用嵌套的 for 循环。

function concatenate(...args) {
    const result = [];
    for (const array of args) for (const { content } of array) result.push(...content);
    return result;
}

const
    var1 = [{ content: [2, 9, 10] }],
    var2 = [{ content: [3, 1, 3] }],
    var3 = [{ content: [9, 1, 8] }];

console.log(...concatenate(var1, var2, var3)); // [2, 9, 10, 3, 1, 3, 9, 1, 8]

Answer 3

您可以对数组使用 .push 方法来连接它们。

let arr1 = [1,2,3];
let arr2 = [3,2,1];
let arr3 = [4,5,6];

function concatenate(...arg){
 let size = arg.length ;
  let finalArr = [];
  
  for(let i = 0; i < size; i++)
    finalArr.push(...arg[i]);
  return finalArr
}

finalArr = concatenate(arr1, arr2, arr3);
console.log(finalArr);

我想用给定次数的扩展语法填充数组 [ ]

I want to populate an array [ ] , with a spread syntax by a given number of times

javascript

class

concatenation

spread-syntax

template-literals