What are the methods to delete array elements in JavaScript?

Methods to delete array elements in JavaScript: 1. Use the splice() method; 2. Use the filter() method; 3. Use the pop() method; 4. Use the shift() method; 5. Use splice Another usage of the () method; 6. Use the delete operator; 7. Use the clear() method. Detailed introduction: 1. Using the splice() method, you can add and delete elements of the array at any position. It accepts two parameters, the starting position and the number of elements to be deleted, etc.

#In JavaScript, there are multiple ways to delete elements from an array. The following are some commonly used methods:

1. Use the splice() method:

The splice() method can add or/and delete elements of the array at any position. It accepts two parameters: the starting position and the number of elements to remove.

For example, to delete the first element from the beginning of the array, you can use the following code:

let arr = [1, 2, 3, 4, 5]; arr.splice(0, 1); // 删除第一个元素，结果为 [2, 3, 4, 5]

To delete multiple elements, just add a second parameter, for example:

let arr = [1, 2, 3, 4, 5]; arr.splice(2, 2); // 从位置2开始删除2个元素，结果为 [1, 2, 5]

2. Use the filter() method:

The filter() method creates a new array. The elements in the new array are determined by checking all elements in the specified array that meet the conditions. . Therefore, we can use it to delete certain elements from the array. For example, to delete all even numbers in the array, you can use the following code:

let arr = [1, 2, 3, 4, 5]; arr = arr.filter(item => item % 2 !== 0); // 结果为 [1, 3, 5]

3. Use the pop() method:

pop() method deletes and returns the array the last element of . If the array is empty, undefined is returned.

For example:

let arr = [1, 2, 3, 4, 5]; arr.pop(); // 删除并返回最后一个元素，结果为 [1, 2, 3, 4]

4. Use the shift() method:

The shift() method deletes and returns the first element of the array. If the array is empty, undefined is returned. Similar to the pop() method, but it removes the first element.

For example:

let arr = [1, 2, 3, 4, 5]; arr.shift(); // 删除并返回第一个元素，结果为 [2, 3, 4, 5]

5. Another usage of the splice() method:

In addition to the above usage, the splice() method also It accepts three parameters: the starting position, the number of elements to remove, and the new elements to add to the array. For example, to add a new element at the beginning of the array and delete the first element, you can use the following code:

let arr = [1, 2, 3, 4, 5]; arr.splice(0, 1, 'newElement'); // 结果为 ['newElement', 2, 3, 4, 5]

6. Use the delete operator:

The delete operator can be used to delete an element of an array. It returns no value (that is, its return value is undefined). Note, however, that this does not change the length of the array. For example:

let arr = [1, 2, 3, 4, 5]; delete arr[2]; // 结果为 [1, 2, undefined, 4, 5]（注意，索引2处的元素被删除了，但数组长度未变）

7. Use the clear() method:

The clear() method is used to clear all elements of the array. It does not change the length of the array, it simply sets all elements to undefined. For example:

let arr = [1, 2, 3, 4, 5]; arr.clear(); // 结果为 [undefined, undefined, undefined, undefined, undefined]（注意，所有元素都被清除了）

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