jquery deletes specified elements in array

In front-end development, we often need to use arrays to store and process data. Sometimes, we need to delete some elements from the array. In this case, we can use jQuery to easily remove specified elements from the array. This article will introduce how to use jQuery to delete elements in an array and how to implement it.

1. jQuery deletes the specified elements in the array

We can use jQuery’s grep method to delete the specified elements in the array. This method returns a new array that does not contain the deleted elements.

The following is a sample code:

var array = [1, 2, 3, 4, 5];
var removeElement = 3;

array = $.grep(array, function(value) {
  return value != removeElement;
});

console.log(array); //[1, 2, 4, 5]

In the above code, we first define an array array, and then define an element to be deleted removeElement . We use the $.grep() method to remove removeElement and reassign the returned new array to array.

In the above example, the $.grep() method accepts two parameters: the first parameter is the array to be operated on, and the second parameter is a function. This function is used to specify filter conditions. A return value of true means retaining the element, and a return value of false means deleting the element. In this example, we use value != removeElement to specify the filter condition, which means to retain elements that are not equal to removeElement.

2. How to delete specified elements in an array

We have already introduced how to use jQuery to delete specified elements in an array. This section describes how to implement this functionality.

1. Find out the subscript of the element to be deleted

First, we need to find out the subscript of the element to be deleted in the array. We can use JavaScript's indexOf() method to find out the index of an element as follows:

var array = [1, 2, 3, 4, 5];
var removeElement = 3;

var index = array.indexOf(removeElement);

console.log(index); //2

In the above code, we use indexOf() Method to find the index of element removeElement. Indexes start counting from 0, so index has a value of 2.

2. Delete elements

After finding the subscript of the element, we can use JavaScript’s splice() method to delete the element. As shown below:

var array = [1, 2, 3, 4, 5];
var removeElement = 3;

var index = array.indexOf(removeElement);

if (index > -1) {
  array.splice(index, 1);
}

console.log(array); //[1, 2, 4, 5]

In the above code, we first find the index of the element removeElement and assign it to the variable index. Then, we determine whether index is greater than -1 (that is, whether the element exists in the array). If it exists, we use the splice() method to remove the element. This method accepts two parameters: the index of the element to be deleted and the number of elements to be deleted. In this example, we are removing an element, so the second parameter is 1.

3. Encapsulate as a jQuery plug-in

In order to facilitate reuse, we can encapsulate the above code into a jQuery plug-in. As shown below:

$.fn.removeFromArray = function(element) {
  var index = this.indexOf(element);

  if (index > -1) {
    this.splice(index, 1);
  }

  return this;
};

In the above code, we add this method to jQuery's prototype object through $.fn so that it can be called in a chain when using this method. This method accepts an element to be deleted as a parameter. We first find the index of the element and then use the splice() method to delete the element. Finally, we return the modified array object itself.

An example of using this plugin is as follows:

var array = [1, 2, 3, 4, 5];
var removeElement = 3;

array.removeFromArray(removeElement);

console.log(array); //[1, 2, 4, 5]

In the above code, we use the removeFromArray() method to remove the element removeElement.

3. Summary

This article introduces how to use jQuery to delete specified elements in an array, and the implementation principle. Through studying this article, we can handle array operations more flexibly and improve code efficiency and development efficiency.

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