在TypeScript中声明一个数组 [英] Declare an array in TypeScript

问题描述

我在Typescript中声明或使用布尔数组时遇到问题，不确定哪个错误。我收到 undefined 错误。我应该使用JavaScript语法还是声明一个新的Array对象？

I'm having trouble either declaring or using a boolean array in Typescript, not sure which is wrong. I get an undefined error. Am I supposed to use JavaScript syntax or declare a new Array object?

创建阵列的正确方法是哪一种？

Which one of these is the correct way to create the array?

private columns = boolean[];
private columns = [];
private columns = new Array<boolean>();

我如何将所有值初始化为假？

How would I initialize all the values to be false?

如何访问这些值，我可以访问它们，如 columns [i] = true; ..？

How would I access the values, can I access them like, columns[i] = true;..?

推荐答案

以下是使用打字稿创建布尔数组的不同方法：

Here are the different ways in which you can create an array of booleans in typescript:

let arr1: boolean[] = [];
let arr2: boolean[] = new Array();
let arr3: boolean[] = Array();

let arr4: Array<boolean> = [];
let arr5: Array<boolean> = new Array();
let arr6: Array<boolean> = Array();

let arr7 = [] as boolean[];
let arr8 = new Array() as Array<boolean>;
let arr9 = Array() as boolean[];

let arr10 = <boolean[]> [];
let arr11 = <Array<boolean>> new Array();
let arr12 = <boolean[]> Array();

您可以使用索引访问它们：

You can access them using the index:

console.log(arr[5]);

并使用push添加元素：

and you add elements using push:

arr.push(true);

创建数组时，您可以提供初始值：

When creating the array you can supply the initial values:

let arr1: boolean[] = [true, false];
let arr2: boolean[] = new Array(true, false);

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