简体中文(ZH-CN) English(EN) 繁体中文(ZH-TW) 日本語(JA) 한국어(KO) Melayu(MS) Français(FR) Deutsch(DE)
Home > Web Front-end > JS Tutorial > body text

JSON and Math use case analysis in JS

php中世界最好的语言
Release： 2018-05-24 13:43:51
Original
2445 people have browsed it

This time I will bring you a case analysis of JSON and Math in JS. What are the precautions for using JSON and Math in JS? Here are the actual cases, let’s take a look.

1.JSON

JSON：

对象格式的字符串
轻量的数据传输格式
Copy after login
Copy after login

Notes: Key name needs to be usedDouble quotes Wrap it up

JOSN has two methods: JSON.parse and JSON.stringify.

  • #JSON.parse converts the string sent from the background into an object. This conversion is needed only when the content of the string is the object.

  • JSON.stringify, converts the object sent from the background into a string. 

<script>
    
    var book = &#39;{"title": "Harry Potter","author": "J K. Rowling","year": 2005,"price": 29.99}&#39;;    
    console.log( JSON.parse( book ) );    
    console.log( book );
//------------------------------------------
    var obj = {
        name: "k",
        age: 25
    };    
    console.log( JSON.stringify( obj ) );
    console.log( obj );
    
</script>
Copy after login
Copy after login

The result is.
JSON and Math use case analysis in JS

2.Math — Part1

Math.ceil

对数向上取整
Copy after login
Copy after login

Math.floor

对数向下取整
Copy after login
Copy after login

Math.random

取0到1的随机数。包括0，但不包括1。
Copy after login
Copy after login

Math.abs

取绝对值
Copy after login
Copy after login

Example:

<script>
    console.log("---------向上取整-----------");
    console.log(Math.ceil(2.3));//3
    console.log(Math.ceil(2.1));//3
    console.log(Math.ceil(2.0));//2
    console.log(Math.ceil(-2.3));//-2
    console.log(Math.ceil(-2.0));//-2
    console.log(Math.ceil(-2.9));//-2
    console.log(Math.ceil(-0.5));//0
    console.log("-------向下取整-------------");
    console.log(Math.floor(2.3));//2
    console.log(Math.floor(2.1));//2
    console.log(Math.floor(2.0));//2
    console.log(Math.floor(-2.3));//-3
    console.log(Math.floor(-2.0));//-2
    console.log(Math.floor(-2.9));//-3
    console.log(Math.floor(-0.5));//-1
    console.log("-------随机数-------------");
    console.log(Math.random());//值是0-1之间的随机数，包括0，不包含1。、
    console.log("-------取绝对值-------------");
    console.log(Math.abs(-2));//2
    console.log(Math.abs(2));//2
</script>
Copy after login
Copy after login

3.Usage of Math.random

1. Take a random integer from 0 to 10

 <script>
        console.log(Math.floor(Math.random()*10));
 </script>
Copy after login
Copy after login

2. Take a number between 5 and 7

<script>
        console.log(Math.random()*2+5);
</script>
Copy after login
Copy after login

4.Math—Part2

Math.max

取到最大数
Copy after login
Copy after login

Math. min

取到最小数
Copy after login
Copy after login

Math.PI

取到圆周率
Copy after login
Copy after login

Usage of Math.PI: 

将弧度转化为角度 deg=rad/Math.PI*180;
将角度转化为弧度 rad=deg/180*Math.PI;
Copy after login
Copy after login
<script>
        console.log("--------Math.PI----------");
        console.log(Math.PI);//3.141592653589793
        console.log("--------Math.max----------");
        console.log(Math.max(1,3,4,5,9,8));//9
        console.log("--------Math.min----------");
        console.log(Math.min(1,3,4,5,9,8));//1
        console.log("--------Math.min,当传入数组返回NAN----------");
        console.log(Math.min([1,3,4,5,9,8]));//NAN
        console.log("-------Math.min,想要将数组内的值传入进去，可以在数组前加入... ----------");
        console.log(Math.min(...[1,3,4,5,9,8]));//1
        console.log(...[1,2,3]);//1,2,3
        console.log(...[1,2,[1,2]]);//1,2,[1,2]
</script>
Copy after login
Copy after login

5.Math— Part3

Math.pow(num,n);

num的n次方。
n个num相乘
Copy after login
Copy after login

Math.sqrt(mun);

num的平方根
Copy after login
Copy after login

Examples

<script>
        console.log("------Math.pow------");
        console.log(Math.pow(3,4));//81
        console.log("------Math.sqrt------");
        console.log(Math.sqrt(4));//2
        console.log(Math.sqrt(3));//1.7320508075688772
</script>
Copy after login
Copy after login

1.JSON

JSON：

对象格式的字符串
轻量的数据传输格式
Copy after login
Copy after login

Notes: The key name needs to be wrapped in double quotes

JOSN has two methods: JSON.parse and JSON.stringify.

  • #JSON.parse converts the string sent from the background into an object. This conversion is needed only when the content of the string is the object.

  • JSON.stringify, converts the object sent from the background into a string. 

<script>
    
    var book = &#39;{"title": "Harry Potter","author": "J K. Rowling","year": 2005,"price": 29.99}&#39;;    
    console.log( JSON.parse( book ) );    
    console.log( book );
//------------------------------------------
    var obj = {
        name: "k",
        age: 25
    };    
    console.log( JSON.stringify( obj ) );
    console.log( obj );
    
</script>
Copy after login
Copy after login

The result is.
JSON and Math use case analysis in JS

2.Math — Part1

Math.ceil

对数向上取整
Copy after login
Copy after login

Math.floor

对数向下取整
Copy after login
Copy after login

Math.random

取0到1的随机数。包括0，但不包括1。
Copy after login
Copy after login

Math.abs

取绝对值
Copy after login
Copy after login

Example:

<script>
    console.log("---------向上取整-----------");
    console.log(Math.ceil(2.3));//3
    console.log(Math.ceil(2.1));//3
    console.log(Math.ceil(2.0));//2
    console.log(Math.ceil(-2.3));//-2
    console.log(Math.ceil(-2.0));//-2
    console.log(Math.ceil(-2.9));//-2
    console.log(Math.ceil(-0.5));//0
    console.log("-------向下取整-------------");
    console.log(Math.floor(2.3));//2
    console.log(Math.floor(2.1));//2
    console.log(Math.floor(2.0));//2
    console.log(Math.floor(-2.3));//-3
    console.log(Math.floor(-2.0));//-2
    console.log(Math.floor(-2.9));//-3
    console.log(Math.floor(-0.5));//-1
    console.log("-------随机数-------------");
    console.log(Math.random());//值是0-1之间的随机数，包括0，不包含1。、
    console.log("-------取绝对值-------------");
    console.log(Math.abs(-2));//2
    console.log(Math.abs(2));//2
</script>
Copy after login
Copy after login

3.Usage of Math.random

1. Take the random integer from 0 to 10

 <script>
        console.log(Math.floor(Math.random()*10));
 </script>
Copy after login
Copy after login

2. Take the random number between 5 and 7 Number

<script>
        console.log(Math.random()*2+5);
</script>
Copy after login
Copy after login

4.Math—Part2

Math.max

取到最大数
Copy after login
Copy after login

Math.min

取到最小数
Copy after login
Copy after login

Math.PI

取到圆周率
Copy after login
Copy after login

Usage of Math.PI: 

将弧度转化为角度 deg=rad/Math.PI*180;
将角度转化为弧度 rad=deg/180*Math.PI;
Copy after login
Copy after login
<script>
        console.log("--------Math.PI----------");
        console.log(Math.PI);//3.141592653589793
        console.log("--------Math.max----------");
        console.log(Math.max(1,3,4,5,9,8));//9
        console.log("--------Math.min----------");
        console.log(Math.min(1,3,4,5,9,8));//1
        console.log("--------Math.min,当传入数组返回NAN----------");
        console.log(Math.min([1,3,4,5,9,8]));//NAN
        console.log("-------Math.min,想要将数组内的值传入进去，可以在数组前加入... ----------");
        console.log(Math.min(...[1,3,4,5,9,8]));//1
        console.log(...[1,2,3]);//1,2,3
        console.log(...[1,2,[1,2]]);//1,2,[1,2]
</script>
Copy after login
Copy after login

5.Math—Part3

Math.pow(num,n);

num的n次方。
n个num相乘
Copy after login
Copy after login

Math.sqrt(mun);

num的平方根
Copy after login
Copy after login

Examples

<script>
        console.log("------Math.pow------");
        console.log(Math.pow(3,4));//81
        console.log("------Math.sqrt------");
        console.log(Math.sqrt(4));//2
        console.log(Math.sqrt(3));//1.7320508075688772
</script>
Copy after login
Copy after login

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

Recommended reading:

Detailed explanation of the implementation steps of PromiseA

Detailed explanation of the steps to highlight the selected li in react implementation

The above is the detailed content of JSON and Math use case analysis in JS. For more information, please follow other related articles on the PHP Chinese website!

Related labels：
javascript math case analysis
source：php.cn
Previous article：Detailed explanation of sorting algorithm examples in front-end Next article：Analysis of how to use bootstarp+table
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Latest Issues
CSS only method to dynamically modify image src on click without using JavaScript I need to change the src of an image on mouse click using only css like img:active{}
From 2024-04-06 19:25:49
0
1
505
Scatterplot points do not maintain values ​​when zooming in d3.js This is my first time using d3.js, so please bear with me. I implemented it as pure JavaSc...
From 2024-04-06 18:16:26
0
1
403
JavaScript hover events on vendor-specific pseudo-elements I have the following htmlinput tag. $("input[type='range']::-webkit-slider-thumb"...
From 2024-04-06 15:35:24
0
1
274
Submit form without button using Javascript/Jquery I'm trying to submit a form without a button by calling a JavaScript function and executin...
From 2024-04-06 14:54:03
0
2
421
Customize the appearance of Bootstrap accordion headers using the CollapseDisplay class I want to style the card title of a panel with class collapseshow. In this example, it's t...
From 2024-04-06 12:53:11
0
1
376
Related Topics
More>
Popular Recommendations
Popular Tutorials
More>
Related Tutorials
Popular Recommendations
Latest courses
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn：Public welfare online PHP training，Help PHP learners grow quickly！