How to find names of all collections using PyMongo?

This is very simple. e.g.

import pymongo
import json

if __name__ == '__main__':
    client = pymongo.MongoClient("localhost", 27017, maxPoolSize=50)
    d = dict((db, [collection for collection in client[db].collection_names()])
             for db in client.database_names())
    print json.dumps(d)

result -> {"database1":["collection1","collection2"...], "database2": [...], ...}, like:

{"test": ["score", "test4", "test5", "test6", "test3", "test7", "user", "test2", "test8"],
 "testdb": ["test5", "test8", "test2", "test9", "test3", "test4", "test6", "test"],
 "local": ["startup_log"],
 "stackoverflow": ["questions"]}

To find the collections, you can use collection_names() - https://pymongo.readthedocs.io/en/stable/api/pymongo/database.html#pymongo.database.Database.collection_names

Update:

The collection_names is deprecated from 3.7 onwards and been replaced by list_collection_names() - https://pymongo.readthedocs.io/en/stable/api/pymongo/database.html#pymongo.database.Database.list_collection_names