Shulou(Shulou.com)06/01 Report--

The knowledge of this article "how to use JavaScript's splice to delete, insert, and replace the array" is not understood by most people, so the editor gives you a summary of the following, detailed contents, clear steps, and a certain reference value. I hope you can get something after reading this article. Let's take a look at this "how to use JavaScript's splice to delete, insert, and replace the array."

1. Delete splice

Writing method

Array.splice (index,n)

Parameter meaning

Index: the starting position in the array where the data needs to be deleted

N: the number of elements to be deleted and the number of data

II. Splice insertion

Writing method

Array.splice (index,0,data1,data2,....)

Parameters.

Index: the starting position in the array where the data needs to be inserted

0: the number of deletions is 0

Data1,data2: elements to be inserted, separated by commas

III. Splice replacement

Writing method

Array.splice (index,n,data1,data2,.)

Parameters.

Index: the starting position of the element to be replaced

N: the number of elements to be replaced, which is essentially deleted

Data1,data2: elements need to be inserted, separated by commas

Generally speaking, splice essentially inserts, deletes and replaces elements by deleting them.

The method of attaching an Operand array

Push is added at the end of the array to return the number of array elements after it is added.

Unshift is added in the array header to return the number of elements after the array is added.

Shift deletes the first element of the array and returns the deleted element

Pop deletes the last element of the array and returns the deleted element

Splice deletes, inserts, and replaces operations that change the value of the original array and return no value.

Slice (start,end) intercepts part of the array and returns the intercepted array. Start is the starting position and end is the end, excluding the position element of the end.

Concat a.concat (b) splices two arrays together and returns a new array after splicing, with the elements inside an at the front of the new array

ToString converts an array to a string and returns a string. The toLocalString implementation is similar to the toString method, but there are compatibility problems under IE, such as spaces before and after characters and decimals in numbers, resulting in changes in the length property, so try to use string.

Join (''&'') converts an array to a string with an interval of & symbols and returns a string

Split (''&'') converts a string with an & symbol bit mark into an array and returns a new array

Sort (function (a function b) {return a murb}) sorts the array. If there is no function function, the new array after the operation is returned by character encoding sort.

Reverse () sorts the array in reverse order, that is, reversing the order of the array and returning the new array in reverse order

ValueOf looks at the values in the object and can return an array of string types, which is not commonly used.

CharAt (index) gets the elements in the order of the strings, returns the elements to be queried, and cannot be used to query array elements.

Var arr = ['baked last month, last month c']

Console.log (arr.valueOf ()); / / valueOf returns 3 ['baked grammar']

Console.log (arr.sort ()); / / sort, returned according to the character encoding [a _ line _ b _ journal _ c]

Console.log (arr.reverse ()); / / the method in reverse order returns [cmenarecoverb]

Arr.splice (1B0pm) / / insert

Console.log (arr); / / returns ["c", "newitem", "b", "a"]

Arr.splice (1meme) / / replace

Console.log (arr) / / returns ["c", "olditem", "b", "a"]

Console.log (arr.unshift ('')) / / header add' ' 'return length 5

Console.log (arr.push ('heihei')); / / add' heihei' to the tail 'and return length 6

Console.log (arr.shift ()) / / return for header deletion

Console.log (arr.pop ()) / / tail deletion returns heihei

Var arr1 = [1, 2, 3, 4]

Console.log (arr.concat (arr1)) / / Array merge returns ["c", "olditem", "b", "a", 1, 2, 3, 4]

Console.log (arr.slice (1p2)) / / Array interception returned ["olditem"]

Console.log (arr [0]) / / returns the element at the specified position of the array

The above is about "how to use JavaScript's splice to delete, insert and replace arrays". I believe we all have some understanding. I hope the content shared by the editor will be helpful to you. If you want to know more about the relevant knowledge, please follow the industry information channel.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.