How javascript deletes elements in an array that specify a subscript

This article will explain in detail how javascript deletes the elements of the specified subscript in the array. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

Javascript delete the specified subscript elements in the array method: 1, the use of array splice () method, syntax "arr.splice (index, 1)"; 2, the use of the delete keyword, syntax "delete arr [index]".

The operating environment of this tutorial: windows7 system, javascript1.8.5 version, Dell G3 computer.

Suppose the array arr has n elements, and now delete the element with the subscript index

There are two ways:

Using the splice () method of the array

Using the delete keyword

1. Splice: after deletion, the following elements are automatically filled to the front.

Arr.splice (index, 1)

For example: there is now an array of arr= ['axiomagy', 'cantiled']

Arr.splice (1,1); / / result arr= ['a subscript 1, delete 1)

Note:

In the above code, we should note that if you want to change the value of arr, manipulating arr will change it directly, instead of writing arr= arr.splice (1jue 1), because the return value of the splice () method is the deleted element.

Add:

Increase in spice:

Arr.splice; / / result arr= ['axiaxiaozhongzhongzhongyuanzhongyuanzhongyuanzhongyuanzhongyuanshou].

Spice replacement:

Arr.splice; / / result arr= ['axiaxiaozhongzhongzhongyuanzhongyuanzhongyuanshou']

Spice replacement 2:

Arr.splice (1 and 2); / / result arr= ['axiomagencience'] (that is, 2 subscript 1 are replaced with 1 "str")

Spice deletes multiple:

Arr.splice (1 ~ 2); / / result arr= ['axiom ~ 2']

2. Delete: after deletion, the subscript location element is undefined

Delete arr [index]

Example:

Delete arr [1]

Empty element can be read and written, length attribute does not exclude empty space, and the return value of empty element bit is undefined.

Console.log (arr [1])

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