如何在TypeScript中将元素添加到数组的末尾?
在TypeScript中,数组是一种表示元素集合的数据类型。数组中的每个元素在数组中都有一个特定的索引或位置,可以使用它们的索引访问或修改数组中的元素。在TypeScript中,数组可以包含相同或不同数据类型的元素。
要在TypeScript中将元素推送到数组的末尾,可以使用`push()`方法。此方法将元素添加到数组的末尾并返回数组的新长度。
语法
用户可以按照以下语法使用`push()`方法将元素添加到数组的末尾。
let numbers: Array<number> = [10, 40, 32]; numbers.push(90);
参数
Array.push()方法包含一个或多个元素作为参数。
元素 - 它是单个元素或用逗号分隔的多个元素,用于插入到数组的末尾。
示例1
在下面的示例中,我们创建了一个数字数组。此外,我们还使用一些数字初始化了数组。
我们使用Array库的`push()`方法将34插入到数组的末尾。此外,我们在34之后插入了904。在输出中,我们可以看到904是最后一个元素,34是倒数第二个元素。
// Creating the array of numbers and initialize with some values. let numbers: Array<number> = [134, 45, 22]; // Push 34 to the end of the array. numbers.push(34); console.log("numbers array after inserting 34 at the end is " + numbers); // Push 904 to the end of the array. numbers.push(904); console.log("numbers array after inserting 904 at the end is " + numbers);
编译后,它将生成以下JavaScript代码:
// Creating the array of numbers and initialize with some values. var numbers = [134, 45, 22]; // Push 34 to the end of the array. numbers.push(34); console.log("numbers array after inserting 34 at the end is " + numbers); // Push 904 to the end of the array. numbers.push(904); console.log("numbers array after inserting 904 at the end is " + numbers);
输出
以上代码将产生以下输出:
numbers array after inserting 34 at the end is 134,45,22,34 numbers array after inserting 904 at the end is 134,45,22,34,904
示例2
在下面的示例中,“strings”是一个包含一些字符串值的字符串数组。在这里,我们传递用逗号分隔的多个字符串作为`push`方法的参数,以便一次性将多个元素插入数组中。`push()`方法按照我们传递字符串作为参数的顺序将元素插入到数组的末尾。
// Creating the array of strings and initialize with some values. let strings: Array<string> = ["Welcome", "To", "The"]; // Push multiple elements at the last of the array strings.push("TutorialsPoint", "!", "Hello", "World!"); console.log( "strings array after inserting the multiple elements at the end: " + strings );
编译后,它将生成以下JavaScript代码:
// Creating the array of strings and initialize with some values. var strings = ["Welcome", "To", "The"]; // Push multiple elements at the last of the array strings.push("TutorialsPoint", "!", "Hello", "World!"); console.log("strings array after inserting the multiple elements at the end: " + strings);
输出
以上代码将产生以下输出:
strings array after inserting the multiple elements at the end: Welcome,To,The,TutorialsPoint,!,Hello,World!
示例3
在下面的示例中,我们创建了Employee接口。该接口包含类变量和方法的声明。之后,我们创建了类型为Employee接口的emp数组,并用Employee的单个对象初始化它。
接下来,我们创建了类型为Employee的new_emp对象,并使用`push()`方法将其插入到emp数组的末尾。我们使用for-of循环打印数组对象。用户可以在输出中看到emp数组包含两个对象,并且new_emp对象插入到最后。
// Create the inteface for the Employee interface Employee { name: string; age: number; isPermenent: boolean; } // Create the array of employee let emp: Employee[] = [{ name: "Shubham", age: 22, is Permenent: true }]; // Create new employee object of type Employee const new_emp: Employee = { name: "Jems", age: 30, isPermenent: false, }; // Push new employee object to emp array emp.push(new_emp); console.log("After inserting the new_emp at the end of the emp array is "); // Iterate through the emp array and print every employee object for (let obj of emp) { console.log("New Employee!"); console.log( "name: " + obj.name + " age: " + obj.age + " isPermenent: " + obj.isPermenent ); }
编译后,它将生成以下JavaScript代码:
// Create the array of employee var emp = [{ name: "Shubham", age: 22, is Permenent: true }]; // Create new employee object of type Employee var new_emp = { name: "Jems", age: 30, isPermenent: false }; // Push new employee object to emp array emp.push(new_emp); console.log("After inserting the new_emp at the end of the emp array is "); // Iterate through the emp array and print every employee object for (var _i = 0, emp_1 = emp; _i < emp_1.length; _i++) { var obj = emp_1[_i]; console.log("New Employee!"); console.log("name: " + obj.name + " age: " + obj.age + " isPermenent: " + obj.isPermenent); }
输出
以上代码将产生以下输出:
After inserting the new_emp at the end of the emp array is New Employee! name: Shubham age: 22 is Permenent: true New Employee! name: Jems age: 30 is Permenent: false
我们学习了如何在数组末尾插入单个或多个元素。在最后一个示例中,我们还学习了如何使用`push()`方法在数组末尾插入对象。