如何检查PyMongo集合是否存在以及是否为空(从集合中全部删除)? [英] How to check in PyMongo if collection exists and if exists empty (remove all from collection)?

问题描述

如何在PyMongo中检入集合是否存在以及是否为空(从集合中全部删除)? 我尝试过

How to check in PyMongo if collection exists and if exists empty (remove all from collection)? I have tried like

collection.remove()

或

collection.remove({})

，但不会删除收藏集.该怎么做?

but it doesn't delete collection. How to do that ?

推荐答案

Pymongo中的示例代码，并带有注释作为解释:

Sample code in Pymongo with comment as explanation:

from pymongo import MongoClient
connection = MongoClient('localhost', 27017) #Connect to mongodb

print(connection.database_names())  #Return a list of db, equal to: > show dbs

db = connection['testdb1']          #equal to: > use testdb1
print(db.collection_names())        #Return a list of collections in 'testdb1'
print("posts" in db.list_collection_names())     #Check if collection "posts" 
                                            #  exists in db (testdb1)

collection = db['posts']
print(collection.count() == 0)    #Check if collection named 'posts' is empty

collection.drop()                 #Delete(drop) collection named 'posts' from db

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