Introduction to various definition methods and common functions of arrays in JavaScript_Basic knowledge

Definition of array:
Method 1.

Copy code The code is as follows:

var mycars=new Array()
mycars[0]="sharejs.com"
mycars[1]="Volvo"
mycars[2]="BMW"

Method 2.
Definition and initialization together:

Copy code The code is as follows:

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

Or:

Copy code The code is as follows:

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

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

Copy code The code is as follows:

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

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

Copy code The code is as follows:

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

Method 3.

Copy code The code is as follows:

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

Javascript arrays do not need to set the length and will expand themselves. The array name.length returns the number of elements

Common functions for JavaScript arrays:
toString(): Convert the array into a string
toLocaleString(): Convert the array into a string
join(): Convert the array into a symbolically connected string
shift(): Remove an element from the head of the array
unshift(): Insert an element at the head of the array
pop(): Delete an element from the tail of the array
push(): Add an element to the tail of the array
concat(): Add to the array Element
slice(): Returns part of the array
reverse(): Sort the array in reverse order
sort(): Sort the array
splice(): Insert, delete or replace an array Element