An introduction to the various methods of defining arrays in javascript and the common functions

  • 2020-03-30 02:56:14
  • OfStack

Definition of array:
Method 1.

var mycars=new Array()

Method 2.
Definition and initialization together:

var mycars=new Array("Saab","Volvo","BMW");


var mycars=["Saab","Volvo","BMW"];

Javascript two-dimensional array, with a one-dimensional array to simulate:
Method 1.

var   arr   =   new   Array(['a','b','c'],['d','e','f']);

Arr [0] returns the first one-dimensional array, and arr[0][0] returns the first element of the first one-dimensional array 'a', the same below.
Method 2.

arr=new   Array();   
for(i=0;i<100;i++) {   
     arr[i]=new   Array(...);   

Method 3.

var  arr=new  Array(   
  new   Array(),   
  new   Array(),   
  new   Array()   

Javascript arrays do not need to be set in length, they are expanded by themselves, and the array name.length returns the number of elements

Common javascript array functions:
ToString () : converts an array to a string
ToLocaleString () : converts an array to a string
Join () : converts an array to a symbolically concatenated string
Shift () : removes an element from the head of the array
Unshift () : inserts an element at the head of the array
Pop () : removes an element from the end of the array
Push () : adds an element to the end of the array
Concat () : adds elements to an array
Slice () : returns the part of the array
Reverse () : reverse sort the array
Sort () : sort an array
Splice () : inserts, removes, or replaces an array element

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