Pymongo Detailed Revision v2

1. Accessing MongoDB Database and printing database names

from pymongo import MongoClient
client = MongoClient('localhost', 27017)
 
dbs = client.list_database_names()
for i in dbs:
    print(i)
client.close()

Output:

admin
booksdb
hrdb
lang
library
local
movieDB
mydatabase
restdb
test
test_info

2. Printing collections from within the database

from pymongo import MongoClient
client = MongoClient('localhost', 27017)
 
db = client['test_info']
coll = db['fruit']
 
db.list_collection_names()

Output:

['fruits', 'fruit', 'student', 'person']

3. Inserting Data

from pymongo import MongoClient
client = MongoClient('localhost', 27017)
 
db = client['test_info']
coll = db['fruit']
 
result = coll.insert_one({'name': 'hello', 'qty':321})
print(result.inserted_id)

Output:

60d8318b8258a00fb8f81173

import json
from pymongo import MongoClient
 
myfile = open(r'Restaurants\intern.json','r')
 
fileLines= myfile.readlines()
fileString = ''
 
for i in fileLines:
    i.strip('\n')
    i.strip('\t')
    fileString += i
 
internDictionary = json.loads(fileString)
internDictionary = internDictionary['intern_details']
 
print(internDictionary)
 
print(type(internDictionary))
 
client = MongoClient('localhost', 27017)
db = client['test_info']
coll = db['person']
x = coll.insert_many(internDictionary)
print(x.inserted_ids)

Output:

[{'name': 'Tan Tan Tan', 'email': 'tttan@lotsofintern.com', 'designation': 'intern'}, {'name': 'Lee Lee Lee', 'email': 'lllee@lotsofintern.com', 'designation': 'intern'}, {'name': 'Ng Ng Ng', 'email': 'nnng@lotsofintern.com', 'designation': 'intern'}]
<class 'list'>
[ObjectId('60d84380ed88c99d19911db1'), ObjectId('60d84380ed88c99d19911db2'), ObjectId('60d84380ed88c99d19911db3')]

4. Data Querying

from pymongo import MongoClient
client = MongoClient("localhost", 27017)
 
db = client['test_info']
coll = db['fruit']
 
query = {'name':{'$regex':'an'}, 'qty':{'$gte':20}}
query = {'address.coords.0':1.3042}
projection ={'_id':0}
 
x = coll.find(query, projection)
for i in x:
    print(i)

Output:

{'name': 'watermelon', 'qty': 31, 'address': {'state': 'singapore', 'postal': 551221, 'coords': [1.3042, 103.8392]}}

5. Updating Data (Set)

from pymongo import MongoClient
client = MongoClient('localhost',27017)
 
db = client['test_info']
print(db.list_collection_names())
coll = db['fruits']
 
query = {'name':'together'}
proj = {'$set':{'name':'applebananatogether'}}
 
x = coll.update_many(query, proj)
print(x.modified_count)
# for i in x:
#     print(i)
 
 
client.close()

Output:

['fruits', 'fruit', 'student', 'person']
2

6. Sorting

from pymongo import MongoClient
client = MongoClient('localhost', 27017)
 
db = client['test_info']
coll = db['fruit']
 
query = {'qty':{'$exists':True}, 'country':{'$exists':False}}
proj = {'_id':0, 'address':0}
 
x = coll.find(query, proj).sort('name',-1)
# The negative 1 makes the sort sorted in reverse alphabetical
for i in x:
    print(i)

Output:

{'name': 'watermelon', 'qty': 31}
{'name': 'pear', 'qty': 15.0}
{'name': 'orange', 'qty': 20.0}
{'name': 'hello', 'qty': 321}
{'name': 'hello', 'qty': 321}
{'name': 'hello', 'qty': 321}
{'name': 'grapefruit', 'qty': 1}
{'name': 'durian', 'qty': 5.0}
{'name': 'applebananatogether', 'qty': 100}
{'name': 'applebananatogether', 'qty': 100}
{'name': 'apple', 'qty': 10.0}

from pymongo import MongoClient
client = MongoClient('localhost', 27017)
 
db = client['test_info']
coll = db['fruit']
 
#remember thisssssss
query = {'$or':[{'name':'hello'}, {'name':'durian'}]}
query = {'name':{'$in':['hello', 'orange']}}
query = {'name':{'$in':['hello', 'orange']}}
query = {"qty":{"$not":{"$gt":10}}}
 
projection = {'_id':0}
 
x = coll.find(query, projection)
for i in x: 
    print(i)

Output:

{'name': 'apple', 'qty': 10.0}
{'name': 'durian', 'qty': 5.0}
{'name': 'lemon', 'qty': '10', 'country': 'SA'}
{'name': 'lime', 'qty': '15', 'country': 'SG'}
{'name': 'apple', 'qty': '40', 'country': 'SG'}
{'name': 'apple', 'qty': '30', 'country': 'SA'}
{'name': 'grape', 'qty': 10, 'country': 'SG'}
{'name': 'grapefruit', 'qty': 1}

7. Misc:

# useful one-liner python scripts
with open('test.txt', 'r') as file: lines = file.readlines()
lines = [i.strip('\n') for i in lines]
print(lines)
 
alphabets = [chr(i) for i in range(65,91)]
print(alphabets)

Output:

['line1', '2', '3', '5', '76', '213']
['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']