Basic knowledge of JavaScript arrays

Array

The concept of array

一A collection of group numbers is called an "array".

var arr = [1,2,3,4,5];

var arr = ["Xiao Ming", "Male", 20, "Institute", "Anhui Province" , ];

Array elements

Each value in the array is called an "array element".

Array index

There are multiple values in the array, each value has a "number", passed "Number" can access each value in the array.
The "number" in the array is also called "subscript" or "index number".
The "subscript number" in the array is a positive integer starting from 0. That is to say: the index of the first array element is 0, the index of the second array element is 1, the index of the third array element is 2, and so on.
The subscript of the first array element must be 0, and the subscript of the last array element is: length-1.
The purpose of using an array is that it is convenient to use a loop to traverse the array.

##Access to array elements

var arr = [10,20,30,40,50];

arr = ["Brother Tao", "Male", 24, "College", "University of Science and Technology Beijing"];

The access method is: the array variable name, followed by a square bracket [], and the [] square bracket is the subscript of the array element. For example: arr[3]

<!DOCTYPE HTML>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <title>php.cn</title>
        <script>
            var arr = ["涛哥" , "男" , 24, "大专" , "北京科技大学" ];
            for(var i=0;i<5;i++){
                document.write(arr[i]+"<br/>");
            }
        </script>
    </head>
    <body>
    </body>
</html>

The length of the array

The length of the array: it is the total number of elements in the array number.

Continuing Learning

new file

<!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>php.cn</title> <script> var arr = ["涛哥" , "男" , 24, "大专" , "北京科技大学" ]; for(var i=0;i<5;i++){ document.write(arr[i]+"<br/>"); } </script> </head> <body> </body> </html>

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Basic knowledge of JavaScript arrays

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