如何在TypeScript中將元素新增到陣列的末尾?
在TypeScript中,陣列是一種表示元素集合的資料型別。陣列中的每個元素在陣列中都有一個特定的索引或位置,可以使用它們的索引訪問或修改陣列中的元素。在TypeScript中,陣列可以包含相同或不同資料型別的元素。
要在TypeScript中將元素推送到陣列的末尾,可以使用`push()`方法。此方法將元素新增到陣列的末尾並返回陣列的新長度。
語法
使用者可以按照以下語法使用`push()`方法將元素新增到陣列的末尾。
let numbers: Array<number> = [10, 40, 32]; numbers.push(90);
引數
Array.push()方法包含一個或多個元素作為引數。
元素 - 它是單個元素或用逗號分隔的多個元素,用於插入到陣列的末尾。
示例1
在下面的示例中,我們建立了一個數字陣列。此外,我們還使用一些數字初始化了陣列。
我們使用Array庫的`push()`方法將34插入到陣列的末尾。此外,我們在34之後插入了904。在輸出中,我們可以看到904是最後一個元素,34是倒數第二個元素。
// 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);
編譯後,它將生成以下JavaScript程式碼:
// 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);
輸出
以上程式碼將產生以下輸出:
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”是一個包含一些字串值的字串陣列。在這裡,我們傳遞用逗號分隔的多個字串作為`push`方法的引數,以便一次性將多個元素插入陣列中。`push()`方法按照我們傳遞字串作為引數的順序將元素插入到陣列的末尾。
// 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 );
編譯後,它將生成以下JavaScript程式碼:
// 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);
輸出
以上程式碼將產生以下輸出:
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,我們建立了Employee介面。該介面包含類變數和方法的宣告。之後,我們建立了型別為Employee介面的emp陣列,並用Employee的單個物件初始化它。
接下來,我們建立了型別為Employee的new_emp物件,並使用`push()`方法將其插入到emp陣列的末尾。我們使用for-of迴圈列印陣列物件。使用者可以在輸出中看到emp陣列包含兩個物件,並且new_emp物件插入到最後。
// 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 ); }
編譯後,它將生成以下JavaScript程式碼:
// 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); }
輸出
以上程式碼將產生以下輸出:
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
我們學習瞭如何在陣列末尾插入單個或多個元素。在最後一個示例中,我們還學習瞭如何使用`push()`方法在陣列末尾插入物件。