python - __call__ vs. __init__：谁得到了论据？谁先被叫到？

Question

可能重复：python中的init和call
有什么区别？

我正在尝试创建一个可调用的类，该类将接受参数，然后将自身作为对象返回。

class User(object):
    def __init__(self, loginName, password):
        self.loginName = loginName

    def __call__(self):
        if self.login():
            return self
        return None

    def login(self):
        database = db.connection
        realUser = database.checkPassWord(self.loginName, self.password)
        return realUser

我的问题是，如果我这样称呼这个对象：

newUserObject = User(submittedLoginName)

之前会__init__被调用__call__吗？应该__init__得到论点还是我应该将论点转移到__call__喜欢

def __call__(self, loginName):

Answer 1

__call__ is only called on an instance that defines itself as callable.

__init__ is the initializer that provided an instance of the class

If you do something like

MyObject()() Then you are initliaizing THEN calling.

Using your own example

class User(object):
    def __init__(self, loginName, password):
        self.loginName = loginName
        self.password = password

    def __call__(self):
        if self.login():
            return self
        return None

    def login(self):
        database = db.connection
        return database.checkPassWord(self.loginName, self.password)

a = User("me", "mypassword")
a = a() # a is now either None or an instance that is aparantly logged in.