Summary of common operations for js,jquery arrays

Summary of common operation of arrays in JS

(1) Shift: Deletes the first item of the original array and returns the value of the deleted element; returns undefined if the array is empty

var a = [1,2,3,4,5];  var B = A.shift (); result a:[2,3,4,5] b:1  

(2) Unshift: Adds a parameter to the beginning of the original array and returns the length of the array

var a = [1,2,3,4,5];  var B = a.unshift ( -2,-1); result a:[-2,-1,1,2,3,4,5] B:7  

Note: The test return value under IE6.0 is always undefined,ff2.0 Test return value is 7, so the return value of this method is not reliable, need to use the return value when the splice can be used instead of this method.

(3) Pop: Deletes the last item of the original array and returns the value of the deleted element; returns undefined if the array is empty

var a = [1,2,3,4,5];  var B = A.pop (); result a:[1,2,3,4] B:5  

(4) Push: Adds a parameter to the end of the original array and returns the length of the array

var a = [1,2,3,4,5];  var B = A.push (6,7); result a:[1,2,3,4,5,6,7] B:7  

(5) Concat: Returns a new array that is a parameter added to the original array.

var a = [1,2,3,4,5];  var B = a.concat (6,7); result a:[1,2,3,4,5] b:[1,2,3,4,5,6,7]  

(6) Splice (Start,deletecount,val1,val2,...) : Deletes the DeleteCount entry starting from the start position and inserts the Val1,val2 from that position,...

var a = [1,2,3,4,5];  var B = a.splice (2,2,7,8,9); result a:[1,2,7,8,9,5] b:[3,4]  

(7) Reverse: Reverse the array

var a = [1,2,3,4,5];  var B = a.reverse ();  

Results a:[5,4,3,2,1] b:[5,4,3,2,1]

(8) sort (orderfunction): Sorts the array by the specified parameters

var a = [1,2,3,4,5];  var B = A.sort (); result a:[1,2,3,4,5] b:[1,2,3,4,5]  

(9) Slice (start,end): Returns a new array that consists of the entries from the original array that specify the starting subscript to the end subscript

var a = [1,2,3,4,5];  var B = a.slice (2,5); result a:[1,2,3,4,5] b:[3,4,5]  

Join (Separator): Sets the element group of the array as a string, separator as a delimiter, and the default comma delimiter if omitted

var a = [1,2,3,4,5];  var B = A.join ("|" ); result a:[1,2,3,4,5] B: "1|2|3|4|5"  

Summary of common operations for js,jquery arrays