Flash cards
Review the key moves
What is the main idea behind Python MongoDB Query?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
___ pymongoPut the learning moves in the order that makes the concept easiest to apply.
Filter the Result
When finding documents in a collection, you can filter the result by using a query object.
The first argument of the find() method is a query object, and is used to limit the search.
Example
Find document(s) with the address "Park Lane 38":
import pymongo
myclient = pymongo.MongoClient("mongodb://localhost:27017/")
mydb = myclient["mydatabase"]
mycol = mydb["customers"]
myquery = { "address": "Park Lane 38" }
mydoc = mycol.find(myquery)
for x in mydoc:
print(x)Advanced Query
To make advanced queries you can use modifiers as values in the query object.
E.g. to find the documents where the "address" field starts with the letter "S" or higher (alphabetically), use the greater than modifier: {"$gt": "S"} :
Example
Find documents where the address starts with the letter "S" or higher:
import pymongo
myclient = pymongo.MongoClient("mongodb://localhost:27017/")
mydb = myclient["mydatabase"]
mycol = mydb["customers"]
myquery = { "address": { "$gt": "S" } }
mydoc = mycol.find(myquery)
for x in mydoc:
print(x)Filter With Regular Expressions
You can also use regular expressions as a modifier.
Regular expressions can only be used to query strings .
To find only the documents where the "address" field starts with the letter "S", use the regular expression {"$regex": "^S"} :
Example
Find documents where the address starts with the letter "S":
import pymongo
myclient = pymongo.MongoClient("mongodb://localhost:27017/")
mydb = myclient["mydatabase"]
mycol = mydb["customers"]
myquery = { "address": { "$regex": "^S" } }
mydoc = mycol.find(myquery)
for x in mydoc:
print(x)