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JSON and Math use case analysis in JS

php中世界最好的语言
php中世界最好的语言Original
2018-05-24 13:43:512508browse

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

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>

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

2.Math — Part1

Math.ceil

对数向上取整

Math.floor

对数向下取整

Math.random

取0到1的随机数。包括0，但不包括1。

Math.abs

取绝对值

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>

3.Usage of Math.random

1. Take a random integer from 0 to 10

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

2. Take a number between 5 and 7

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

4.Math—Part2

Math.max

取到最大数

Math. min

取到最小数

Math.PI

取到圆周率

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;
<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>

5.Math— Part3

Math.pow(num,n);

num的n次方。
n个num相乘

Math.sqrt(mun);

num的平方根

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>

1.JSON

JSON：

对象格式的字符串
轻量的数据传输格式

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>

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

2.Math — Part1

Math.ceil

对数向上取整

Math.floor

对数向下取整

Math.random

取0到1的随机数。包括0，但不包括1。

Math.abs

取绝对值

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>

3.Usage of Math.random

1. Take the random integer from 0 to 10

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

2. Take the random number between 5 and 7 Number

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

4.Math—Part2

Math.max

取到最大数

Math.min

取到最小数

Math.PI

取到圆周率

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;
<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>

5.Math—Part3

Math.pow(num,n);

num的n次方。
n个num相乘

Math.sqrt(mun);

num的平方根

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>

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!

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