Resolve javascript arrays (and add and remove jason elements)

Javasscript removes arrays in 3 ways

1, with shift() method

var chaomao=[1,2,3,4,5]
var chaomao.shift()//得到1
alert(chaomao)//[2,3,4,5]

2, with pop() method

var chaomao=[1,2,3,4,5]
var chaomao.pop()//得到5
alert(chaomao)//[1,2,3,4]

The previous method can only manipulate the beginning and end of the array, the middle item cannot be operated, and if you want to manipulate the middle item, use the space method

3, with the splice method

Modifications:

var chaomao=[1,2,3,4,5]
chaomao.splice(2,1,8,9)
alert(chaomao)//1,2,8,9,4,5

The first argument is the array position to prepare the operation, the second argument is the number of array items after the operation position, and the third is, after the replaced content
The example is that the item after position 2 is replaced by 8,9, starting with the array position 2 (that is, the item with the value 3, the array substation starts at 0).
If you change the second parameter to 2, that is,chaomao.splice (2, 2, 8, 9), that is, the two items after position 2 are replaced by 8, 9, and the printed result is 1, 2, 8, 9, 5, 3 and 4
It should be noted here that the number of items replaced does not have to be equal to the number of items replaced, 1 item can be replaced with 3 items, 5 items can also be replaced with 2 items, based on this principle, we use this method to add and delete the array

Delete:

var chaomao=[1,2,3,4,5]
chaomao.splice(2,1)
alert(chaomao)//1,2,4,5

In the example above, replace 1 item after position 2 in chaomao with an empty one, because there is nothing behind it, and as a result, 3 items are deleted

Add an action:

var chaomao=[1,2,3,4,5]
chaomao.splice(2,0,8,9)
alert(chaomao)//1,2,8,9,3,4,5

In the example above, replacing 0 items after position 2 in chaomao with 8,9 is equivalent to adding two items
In fact, deletion and addition are just two derivatives of the splice modification method

The method by which javasscript deletes objects

var p ={
"name": “chaomao”,
"age":45,
"sex":"male"
};
delete p.name
for(var i in p){
console.log(i);//输出age,sex，name项已经被删除了
}

var json = {}; // 如果json已经定义就跳过
json[text] = value;
json.text2 = value2;  // 此时text2必须符合变量名标准，否则得使用数组方式赋值

var json = {}; // 如果json已经定义就跳过
json[text] = value;
json.text2 = value2;  // 此时text2必须符合变量名标准，否则得使用数组方式赋值

The difference between a js array and a jason

1. Define a one-dimensional array:

var s1=new Array();
s1, 2, 3, 4, or s1, 0, s1, 1, 2, s1, 3, s1, 3, s1, 4, 4;
alert(s1[0]);
The result is 1;

2. Define a two-dimensional group:

var s1=new Array();
var s1=[[3,1],[2,3,4],3,[4,5,6,7,8]];
alert(s1[1][0]);
The result is 2;

Second, define the json object

var status_process = {
" name5" : '闲置期',
"name1" : '播种期',
"name2" : '苗期',
"name3" : '生长期',
"name4" : '采收期'
 }    
alert(status_process);

var s1="{";
var s2 = " 'name5' : '闲置期',  'name1' : '播种期','name2' : '苗期','name3' : '生长期','name4' : '采收期'";
var s3="}";
var status_process=s1+s2 +s3；

var status_process = {
name5 : '闲置期',
name1 : '播种期',
name2 : '苗期',
name3 : '生长期',
name4 : '采收期'
};
alert(status_process["name5"]);
alert(status_process.name5);

var status_process = {
 name5 : {name3:'空闲闲置期'},
 name1 : '播种期',
 name2 : '苗期',
 name3 : '生长期',
 name4 : '采收期'
};
alert(status_process["name5"]["name3"]);
alert(status_process.name5.name3);