Python爬虫25-MongoDB练习题

测试数据

var persons = [{
	name:"jim",
	age:25,
	email:"[e-mail]",
	c:89,m:96,e:87,
	country:"USA",
	books:["JS","C++","EXTJS","MONGODB"]
},
{
	name:"tom",
	age:25,
	email:"[e-mail]",
	c:75,m:66,e:97,
	country:"USA",
	books:["PHP","JAVA","EXTJS","C++"]
},
{
	name:"lili",
	age:26,
	email:"[e-mail]",
	c:75,m:63,e:97,
	country:"USA",
	books:["JS","JAVA","C#","MONGODB"]
},
{
	name:"zhangsan",
	age:27,
	email:"[e-mail]",
	c:89,m:86,e:67,
	country:"China",
	books:["JS","JAVA","EXTJS","MONGODB"]
},
{
	name:"lisi",
	age:26,
	email:"[e-mail]",
	c:53,m:96,e:83,
	country:"China",
	books:["JS","C#","PHP","MONGODB"]
},
{
	name:"wangwu",
	age:27,
	email:"[e-mail]",
	c:45,m:65,e:99,
	country:"China",
	books:["JS","JAVA","C++","MONGODB"]
},
{
	name:"zhaoliu",
	age:27,
	email:"[e-mail]",
	c:99,m:96,e:97,
	country:"China",
	books:["JS","JAVA","EXTJS","PHP"]
},
{
	name:"piaoyingjun",
	age:26,
	email:"[e-mail]",
	c:39,m:54,e:53,
	country:"Korea",
	books:["JS","C#","EXTJS","MONGODB"]
},
{
	name:"lizhenxian",
	age:27,
	email:"[e-mail]",
	c:35,m:56,e:47,
	country:"Korea",
	books:["JS","JAVA","EXTJS","MONGODB"]
},
{
	name:"lixiaoli",
	age:21,
	email:"[e-mail]",
	c:36,m:86,e:32,
	country:"Korea",
	books:["JS","JAVA","PHP","MONGODB"]
},
{
	name:"zhangsuying",
	age:22,
	email:"[e-mail]",
	c:45,m:63,e:77,
	country:"Korea",
	books:["JS","JAVA","C#","MONGODB"]
}]

for(var i = 0;i<persons.length;i++){
	db.persons.insert(persons[i])
}

var persons = db.persons.find({name:"jim"})
while(persons.hasNext()){
	obj = persons.next();
        print(obj.books.length)
}

1、查询年龄大于25小于27的name，age

db.persons.find({age:{$gt:25,$lt:27}},{name:1,age:1,_id:0})

2、查询出不是美国的name

db.persons.find({country:{$ne:'USA'}},{name:1,country:1,_id:0})

3、查询国籍是中国或者美国的学生信息

db.persons.find({$or:[{country:'China'},{country:'USA'}]},{name:1,country:1,_id:0})

4、查询语文成绩大于85或者英语成绩大于90的学生信息

c：语文成绩
e：英语成绩

db.persons.find({$or:[{c:{$gt:85}},{e:{$gt:90}}]},{c:1,e:1,name:1,_id:0})

5、查询出名字中存在"li"的学生信息

第一种

db.persons.find({name:/li/},{name:1,_id:0})

第二种

db.persons.find({name:/l.*?i/},{name:1,_id:0})

6、查询喜欢看MONGODB和PHP的学生

$all：所有包含的

 db.persons.find({books:{$all:['MONGODB','PHP']}},{name:1,books:1,_id:0})

7、查询第二本书是JAVA的学生信息

利用索引下标查询
第二本：‘books.1’

db.persons.find({'books.1':'JAVA'},{name:1,books:1,_id:0})

8、查询喜欢的书数量是4本的学生

$size：数量

db.persons.find({books:{$size:4}},{name:1,books:1,_id:0})

9、查询出persons中一共有多少国家分别是什么

distinct：返回唯一不同的值，去重

db.persons.distinct('country')

本文地址：https://blog.csdn.net/weixin_47133012/article/details/108723595