如何在JavaScript中创建二维数组

灰太狼 2023-10-04 12:57 11阅读 0赞

二维[数组][Link 1]是一组共享相同名称的项目。二维数组是数组的数组，也就是说，创建一维数组对象的数组。它们以行和列的形式排列成矩阵。

[JavaScript][]建议了一些创建二维数组的方法。

### **数组构造[¶][Link 2]** ###

您可以使用数组构造函数和[for][]循环来创建2D数组，如下所示：

const m = 4;
    const  n = 5;
    let arr = new Array(m); // create an empty array of length n
    for (var i = 0; i < m; i++) {
      arr[i] = new Array(n); // make each element an array
    }
    console.log(arr); //  Output: [ [ <5 empty items> ], [ <5 empty items> ], [ <5 empty items> ], [ <5 empty items> ] ]

### **数组文字符号[¶][Link 3]** ###

文字符号方法也可以用于创建2D数组：

const m = 4;
    const  n = 5; // Note 2nd dimention is not relevant here
    let arr = [];
    for (var i = 0; i < m; i++) {
      arr[i] = [];
    }
    console.log(arr); // Output: [ [], [], [], [] ]

### **所述Array.from（）方法[¶][Link 4]** ###

该Array.from()方法将从具有length属性或可迭代对象的任何[JavaScript对象中][JavaScript 1]返回一个数组对象。

const m = 4;
    const  n = 5;
    let arr = Array.from(Array(m), () => new Array(n));
    console.log(arr); //  Output: [ [ <5 empty items> ], [ <5 empty items> ], [ <5 empty items> ], [ <5 empty items> ] ]

### **Array.prototype.map（）方法[¶][Link 5]** ###

您也可以直接调用[map（）][map]函数：

const m = 4;
    const  n = 5;
    let arr = Array(m).fill().map(() => Array(n));
    console.log(arr);  //  Output: [ [ <5 empty items> ], [ <5 empty items> ], [ <5 empty items> ], , [ <5 empty items> ] ]

### **多维数组[¶][Link 6]** ###

[多维数组][Link 7]在JavaScript中称为另一个数组内部的数组，因为它们是使用另一个一维数组创建的。

它们可以具有两个以上的维度。二维数组也称为矩阵或行和列的表。

[Link 1]: https://www.w3docs.com/learn-javascript/javascript-array.html
[JavaScript]: https://www.w3docs.com/learn-javascript.html
[Link 2]: https://www.w3docs.com/snippets/javascript/how-to-create-a-two-dimensional-array-in-javascript.html#array-constructor-2
[for]: https://www.w3docs.com/learn-javascript/javascript-loops.html
[Link 3]: https://www.w3docs.com/snippets/javascript/how-to-create-a-two-dimensional-array-in-javascript.html#array-literal-notation-5
[Link 4]: https://www.w3docs.com/snippets/javascript/how-to-create-a-two-dimensional-array-in-javascript.html#the-array-from-method-8
[JavaScript 1]: https://www.w3docs.com/learn-javascript/javascript-objects.html
[Link 5]: https://www.w3docs.com/snippets/javascript/how-to-create-a-two-dimensional-array-in-javascript.html#the-array-prototype-map-method-11
[map]: https://www.w3docs.com/learn-javascript/array-methods.html#map
[Link 6]: https://www.w3docs.com/snippets/javascript/how-to-create-a-two-dimensional-array-in-javascript.html#multidimensional-arrays-14
[Link 7]: https://www.w3docs.com/learn-javascript/javascript-array.html#multidimensional-arrays