With the development of front-end technology, JavaScript has become a very popular programming language. One of the most commonly used libraries is jquery. The power of jquery lies in its simplicity and practicality. jquery's concise statements allow us to complete more work in JavaScript. In this article, we mainly discuss how jquery traverses an array and deletes elements.
First, let us understand how jquery traverses an array. There is an each() function in jquery, which can traverse any iterable object.
For example, if we have an array arr, we can iterate over the array using the following method:
$.each(arr, function (index, item) { // do something with the item });
In the above code, the $.each() function accepts two parameters, the first The first is the object to be traversed, and the second is a callback function. The callback function will be called on each iteration. In the callback function, the parameter index represents the index position of the current iteration, and the parameter item represents the element of the current iteration. You can write some logic in the callback function to handle each iterated element.
Let us introduce how to use jquery to delete elements from an array.
Method to delete a single element
If you want to delete a specific element from the array, you can use the following code:
$.each(array, function(index, item) { if (item === targetItem) { array.splice(index, 1); return false; } });
This code uses the each() function to iterate array, and when the element to be deleted is found, use the splice() function to delete the element. The splice() function is a method provided by JavaScript to delete array elements. It accepts two parameters: the position of the element to be deleted and the number of elements to be deleted. Here we set the number of elements to delete to 1 since we only want to delete a single element.
We use return false in the callback function to stop the $.each() function from continuing to iterate the array. This is because we only want to delete one element, and if we don't interrupt the iteration, the code will continue executing and delete other elements that are the same as the target element.
Methods to delete multiple elements
If you want to delete multiple elements from the array, you can use the following code:
var itemsToRemove = [targetItem1, targetItem2, targetItem3]; $.each(array, function(index, item) { if ($.inArray(item, itemsToRemove) !== -1) { array.splice(index, 1); return false; } });
In this example, we create a named An array of itemsToRemove containing the elements to be deleted. We iterate through the array using the $.each() function and when we find the element we want to delete, we use the splice() function to delete the element.
Similar to the previous example, we use return false to interrupt the iteration and stop searching.
It should be noted that in this example, we use the inArray() function provided by jquery to find whether the array contains the specified element. If the element is an object, you must use $.inArray() in the inArray() function because in this case JavaScript will convert the object to a string.
Summary
In this article, we discussed jquery's method of traversing an array and how to delete elements in an array using jquery. When iterating through the array, we can use the each() function to access each element and use the splice() function to complete the operation when we need to remove an element. In addition, we can also use the inArray() function provided by jquery to find elements in the array. These techniques can allow us to operate JavaScript arrays more efficiently, thus improving our development efficiency.
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