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This article mainly introduces the ECMAScript3 array operation methods, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let Xiaobian take you to understand.

Operation method of ECMAScript3 array

Format input array

You can specify that the output is a connection string between elements.

A = [2017, 8, 29]

A.jion ("/"); / / output result: "2017-8-29"

Reverse the order of elements

A = [1, 2, 3]

A.reverse (); / / = > a = [3,2,1]

Array sorting

A = [2017, 8, 29]

A.sort (); / / = > a = [8,29,2017]

You can customize the collation by passing a comparison function.

A = [2017, 8, 29]

A.sort (function (a, b) {

Return b-a; / / descending

}

); / / = > a = [2017, 29, 8]

Array join

A = [1, 2, 3]

A.concat (4,5); / / = > a = [1,2,3,4,5]

A.concat ([6, 9, 10]); / / a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Get array fragments

A = ["A", "B", "C", "D", "E"]

/ / specify the start position and the end position (not included).

A.slice (0,2); / / return ["A", "B"]

/ / specify only the start position

A.slice (3); / / return ["D", "E"]

/ / specify the start position, the end position calculated from the last element

A.slice (- 5,-3); / / return ["A", "B"]

Specify an interval to replace array elements

A = [1, 2, 3, 4, 5]

/ / 2 elements that will start with the second element (index value 1)

/ / replace with the 3 elements following the beginning of the third parameter of splice

B = a.splice (1,2, "A", [100.20], "B")

After the execution of this program, the content of the array an is [1, "A", [10jue 20], "B", 4je 5], and the array b of the return value is [2,3]. If you specify only the first parameter, it is sliced from the source array and returns all elements after the specified position; if you specify the first two parameters, it is equivalent to digging out a portion of the source array.

Add and remove elements at the tail

A = [1, 2, 3]

A.push (4,5); / / = > a = [1,2,3,4,5]

A.pop (); / / = > a = [1,2,3,4]

Insert and delete elements in the header

A = [1, 2, 3]

A.unshift (4, 5, 6); / / > a = [4, 5, 6, 1, 2, 3]

A.shift (); / / = > a = [5,6,1,2,3]

Convert an array to a string

["I", "You", "Who"] .toString (); / / = > "iPertinent who"

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