[JavaScript] common APIs for array objects

Concat ()

Concatenate two or more arrays and return results

 
VaRA = [1, 2, 3];VaRB = A. Concat (6, 7); Console. Log ();//[1, 2, 3]Console. Log (B );//[1, 2, 3, 6, 7]
 

Join (STR)

All elements of the array are separated by STR, which is separated by commas by default.

 
VaRA = [1, 2, 3]VaRB = A. Join ('|'); Console. Log ();//[1, 2, 3]Console. Log (B );//"1 | 2 | 3"
 

Pop ()

Delete and return the value of the last element of the array

 
VaRA = [1, 2, 3];VaRB =A. Pop (); console. Log ();//[1, 2]Console. Log (B );//3
 

Push ()

Add one or more elements to the end of the array and return the length of the new array.

 
VaRA = [1, 2, 3];VaRB = A. Push ('4', '5'); Console. Log ();//[1, 2, 3, 4, 5]Console. Log (B );//5
 

Reverse ()

Reverse the order of elements in the array

VaRA = [1, 2, 3, 4, 5];VaRB =A. Reverse (); console. Log ();//[5, 4, 3, 2, 1]Console. Log (B );//[5, 4, 3, 2, 1]
 

Shift ()

Delete and return the first element of the array

 
VaRA = [1, 2, 3];VaRB =A. Shift (); console. Log ();//[2, 3]Console. Log (B );//1
 

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 ();  //  [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 ); //  [] 

Sort (func)

Sorts arrays by specified parameters

Note:Func must return a value.

Negative value. The first parameter is smaller than the second parameter and is placed first.

Zero, equal.

A positive value. The first parameter is later than the second parameter.

  var  A = [000000, ];   var  B = . sort (); console. log (a);  ///   [1, 10, 2, 3]  console. log (B); ///  , 2, 3]   var  num =  function   (x, y) {  return  X- Y ;}  var  C = . sort (Num); console. log (a);  ///   [1, 2, 3, 10]  console. log (c); ///  , 3, 10]  

Splice (START, deletecount, val1, val2 ,···)

Removes one or more elements from an array, inserts a new element at this position, and returns the removed element.

 
VaRA = [1, 2, 3, 4, 5];VaRB = A. splice (2,2, 7,8); Console. Log ();//[1, 2, 7, 8, 5]Console. Log (B );//[3, 4]
 

Unshift (val1, val2 ,···)

Insert the specified element into the starting position of the array and return the new length.

VaRA = [1, 2, 3];VaRB = A. unshift (-2,-1); Console. Log ();//[-2,-,]Console. Log (B );//5
 

Tostring ()

Convert the elements of the array into strings, separate them with commas, and connect them.

 
VaRA = [1, 2, 3, 4, 5];VaRB =A. tostring (); console. Log ();//[1, 2, 3, 4, 5]Console. Log (B );//"1, 2, 3, 4, 5"