したがって、構文に関しては、いくつかの問題があります。いくつかのチュートリアルをさまざまな方法で混合しているようです。それで、最初に私はあなたのコードで何が起こっているのかを説明し、あなたが見ているものを見ている理由を説明します：
import pymongo
class mongoDB(): # you don't need ()'s here - only if you are inheriting classes
# you could inherit from object here, which is a good practice
# by doing class mongoDb(object):, otherwise you can just take
# them out
conn = object # here, you're defining a class member - global for all instances
# generally, you don't instantiate an object pointer like this,
# you would set it to None instead. It won't fail doing this,
# but it's not "right"
def __init__(self):
# the __init__ method is the constructor method - this will
# allow you to initialize a particular instance of your class, represented
# by the self argument. This method is called when you call the class, i.e.
# inst = mongoDb()
# in this case, the conn variable is not a global. Globals are defined
# at the root module level - so in this example, only pymongo is a global
# conn is a class member, and would be accessed by doing mongoDB.conn
global conn
# with that being said, you're initializing a local variable here called conn
# that is not being stored anywhere - when this method finishes, this variable
# will be cleaned up from memory, what you are thinking you're doing here
# should be written as mongoDB.conn = pymongo.Connection("localhost", 27017)
conn = pymongo.Connection("localhost",27017)
def CreateCollection(name =""):
# there is one of two things you are trying to do here - 1, access a class
# level member called conn, or 2, access an instance member called conn
# depending on what you are going for, there are a couple of different ways
# to address it.
# all methods for a class, by default, are instance methods - and all of them
# need to take self as the first argument. An instance method of a class
# will always be called with the instance first. Your error is caused because
# you should declare the method as:
# def CreateCollection(self, name = ""):
# The alternative, is to define this method as a static method of the class -
# which does not take an instance but applies to all instances of the class
# to do that, you would add a @staticmethod decorator before the method.
# either way, you're attempting to access the global variable "conn" here,
# which again does not exist
# the second problem with this, is that you are trying to take your variable
# argument (name) and use it as a property. What python is doing here, is
# looking for a member variable called name from the conn object. What you
# are really trying to do is create a collection on the connection with the
# inputed name
# the pymongo class provides access to your collections via this method as a
# convenience around the method, create_collection. In the case where you
# are using a variable to create the collection, you would call this by doing
# conn.create_collection(name)
# but again, that assumes conn is what you think it is, which it isn't
dbCollection = conn.name
return dbCollection
if __name__ == '__main__':
# here you are just creating a pointer to your class, not instantiating it
# you are looking for:
# database = mongoDB()
database = mongoDB
# this is your error, because of the afore mentioned lack of 'self' argument
collection = database.CreateCollection("Hello")
コードを「フロー」にする方法については、Pep-8（http://www.python.org/dev/peps/pep-0008/）コーディングスタイルガイド（非常に役立つ）をご覧ください。 pythonically。
何が起こっているのかを説明するためにコードを調べた後、これが最終的にやろうとしていることです。
import pymongo
class MongoDB: # Classes generally are camel-case, starting with uppercase
def __init__(self, dbname):
# the __init__ method is the class constructor, where you define
# instance members. We'll make conn an instance member rather
# than a class level member
self._conn = pymongo.Connection("localhost", 27017)
self._db = self._conn[dbname]
# methods usually start with lowercase, and are either camel case (less desirable
# by Python standards) or underscored (more desirable)
# All instance methods require the 1st argument to be self (pointer to the
# instance being affected)
def createCollection(self, name=""):
return self._db[name]
if __name__ == '__main__':
# you want to initialize the class
database = MongoDB("Hello")
collection = database.createCollection("MyTable")
そのことを考えると、このクラスラッパーを作成する目的は何ですか？同じことを次のように書くことができます：
import pymongo
conn = pymongo.Connection('localhost', 27017)
database = conn["Hello"]
collection = database["MyTable"]
pymongoデータベースをラップするより大きなAPIを作成しようとしている場合は、すでに構築されているいくつかのORMモジュールを調べることをお勧めします。そこにはいくつかあります-MongoDBで利用できるものが100％確実ではありませんが、私が使用しているもの（私は偏っています、私はそれを書きました）はORBと呼ばれ、http：//docs.projexsoftware.com/で見つけることができますapi / orb