What are the operation methods of ECMAScript3 array
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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