JavaScript array objects Common API functions summary (join, INSERT, delete, reverse, sort, etc.) _javascript tips

The examples in this article describe the common API functions for JavaScript array objects. Share to everyone for your reference, specific as follows:

1. Concat ()

Connect two or more arrays and return the results

var a = [1,2,3];
var B = A.concat (6,7);
Console.log (a); [1,2,3]
Console.log (b);//[1,2,3,6,7]

2. Join (STR)

Separates all elements of an array with STR, with the default comma separated

var a = [1,2,3]
var b = a.join (' | ');
Console.log (a); [1,2,3]
Console.log (b);//"1|2|3"

3. Pop ()

Deletes and returns the value of the last element of the array

var a = [1,2,3];
var B = A.pop ();
Console.log (a); [1,2]
Console.log (b);//3

4. Push ()

Adds one or more elements to the end of the array and returns the new array length

var a = [1,2,3];
var B = A.push (' 4 ', ' 5 ');
Console.log (a); [1,2,3,4,5]
Console.log (b);//5

5. Reverse ()

Reverses the order of elements in an array

var a = [1,2,3,4,5];
var B = A.reverse ();
Console.log (a); [5,4,3,2,1]
Console.log (b);//[5,4,3,2,1]

6. Shift ()

Deletes and returns the first element of the array

var a = [1,2,3];
var B = A.shift ();
Console.log (a); [2,3]
console.log (b);//1

7. Slice (start,end)

Returns the selected element from an existing array

var a = [1,2,3,4,5];
var B = A.slice (0,-1);
var c = A.slice (1,3);
var d = a.slice (1);
var e = A.slice (2,-2);
var f = a.slice (3,1);
Console.log (a); [1,2,3,4,5]
Console.log (b);//[1,2,3,4]
Console.log (c);//[2,3]
Console.log (d);//[2,3,4,5]
Console.log (e); [3]
console.log (f);//[]

8. Sort (func)

Sort the array by the specified parameters

Note: Func must return a value.

Negative value, the first argument is smaller than the second argument, and is in front.

0, equal.

Positive values, the first parameter is larger than the second parameter, and is in the back.

var a = [1,2,10,3];
var B = A.sort ();
Console.log (a); [1,10,2,3]
Console.log (b);//[1,10,2,3]
var num = function (x,y) {return
  x-y;
}
var c = a.sort (num);
Console.log (a); [1,2,3,10]
Console.log (c);//[1,2,3,10]

9. Splice (start,deletecount,val1,val2,)

Removes one or more elements from an array and inserts a new element at that location, returning the removed element

var a = [1,2,3,4,5];
var B = A.splice (2,2,7,8);
Console.log (a); [1,2,7,8,5]
Console.log (b);//[3,4]

Unshift (val1,val2,)

Inserts the specified element at the beginning of the array and returns a new length

var a = [1,2,3];
var B = A.unshift ( -2,-1);
Console.log (a); [ -2,-1,1,2,3]
Console.log (b);//5

ToString ()

Converts the elements of an array to strings, separated by commas, and connected

var a = [1,2,3,4,5];
var B = a.tostring ();
Console.log (a); [1,2,3,4,5]
Console.log (b);//"1,2,3,4,5"

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