How to remove a subarray from an array in javascript

In development, processing arrays is one of the frequently used operations. Sometimes it is necessary to delete an array from an array, especially a large array containing multiple sub-arrays. In this article, we will introduce how to delete a specific sub-array from an array using JavaScript.

1. Use the splice() function

JavaScript’s splice() function can be used to delete an element in an array, and the operation is more flexible. We can use the splice() function to delete elements at any position, including subarrays.

The specific steps are as follows:

• First, find the index position of the subarray you want to delete.
• Then, use the splice() function to remove the subarray from the array.

The sample code is as follows:

let arr = [[1, 2], [3, 4], [5, 6], [7, 8]];
let index = arr.findIndex((item) => item[0] === 3 && item[1] === 4);
if (index > -1) {
  arr.splice(index,1);
}
console.log(arr); // output: [[1, 2], [5, 6], [7, 8]]

In this example, we first create a large array containing multiple subarrays, and then use the findIndex() method to obtain the subarray to be deleted. The index position of the array. Finally, use the splice() function to remove the array from the original array and output all remaining subarrays.

2. Use the filter() function

JavaScript's filter() function can be used to create a new array containing all elements that meet the conditions. We can use the filter() function to create a new array without the subarray we want to delete.

Look at the code directly:

let arr = [[1, 2], [3, 4], [5, 6], [7, 8]];
let newArray = arr.filter((item) => !(item[0] === 3 && item[1] === 4));
console.log(newArray); // output: [[1, 2], [5, 6], [7, 8]]

In this example, we first create a large array containing multiple subarrays, and then use the filter() function to create a new subarray containing There are not all elements of the subarray to delete. Finally, we print the results to the console.

3. Use for loop

If you need to delete a specific sub-array from an array without using any JavaScript built-in functions, a for loop is a feasible method.

The specific steps are as follows:

• First, find the index position of the subarray to be deleted.
• Then, use a for loop to traverse the array and remove the elements you want to delete from it.

The sample code is as follows:

let arr = [[1, 2], [3, 4], [5, 6], [7, 8]];
let index = arr.findIndex((item) => item[0] === 3 && item[1] === 4);
if (index > -1) {
  for (let i = index; i < arr.length - 1; i++) {
    arr[i] = arr[i + 1];
  }
  arr.length--;
}
console.log(arr); // output: [[1, 2], [5, 6], [7, 8]]

In this example, we first create a large array containing multiple subarrays, and then use the findIndex() method to obtain the subarray to be deleted. The index position of the array. Then, use a for loop to iterate through the original array and delete the specified subarray from it. Finally, we print the results to the console.

Summary

This article introduces three methods to delete specific subarrays from a large array containing multiple subarrays, using the splice() function, filter() function and for loop. Just choose the appropriate method for different situations. JavaScript provides various methods to manipulate data. Choosing the method that suits you can improve development efficiency.

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