如何使用pymongo构造变量查询

Question

I have the string s = "users.count()"

and the db object.

How do I combine db and s such that print combination(db,s) prints the total number of users?

I tried db[s] and db+s and both don't work.

Thanks!

Answer 1

Check the docs
1) Initialize your connection first

from pymongo import MongoClient
client = MongoClient('localhost', 27017)

2) Select your db

db = client["db_name"] #replace db_name with your database name

3) Run count() on your collection. Say, your collection name is users

print db.users.count()
# OR
print db["users"].count()

If you have something like s = "users.count()" and want to execute s . Try:

collection = s.split(".")[0]
function_call = s.split(".")[-1].strip("()")
print getattr(db[collection],function_call)()