python中带有__init__的对象

Question

I have written some python code:

class key(object):
    def __init__(self,name):
        object.__init__(self,age)
        this.name = name
        this.age = age

    def somefunction(self):
        print "yay the name is %d" % self.name

baby = key('radan',20)
baby.somefunction()

When I create an instance of key with baby = key('radan',20) , I got a TypeError. I don't know why I am getting this error. Is it because of object.__init__(self,age) ?

If yes, please help me in explaining why we use object.__init__(self,age) and what the purpose of that is and help me solve this code.

Answer 1

Some pointers:

class Key(object): # in Python, classes are usually named with a starting capital

    def __init__(self, name, age): # name all your arguments beside self

        self.name = name # use self.name, not this.name
        self.age = age

    def somefunction(self):

        print "yay the name is %s" % self.name

baby = Key('radan',20)
baby.somefunction()
# output: yay the name is radan

Actually, you can can name the self instance parameter whatever you like in Python (even this ), but it makes the code harder to read for other people, so just use self .

You don't have to use object.__init__(self, name, age) here. If you remove that line and implement the changes above, your code will work just fine.

Answer 2

When you do baby = key('radar', 20) you are actually passing three arguments: the instance, the name and the age . However your initialiser is defined to take exactly two arguments so you get a TypeError .

self is the argument implicitly passed when referring to an instance of an object.

For your __init__ function, I would just do:

def __init__(self, name, age):
    self.name = name
    self.age = age

So we can assign the arguments passed as attributes to the current instance, conventionally called self .

It makes no sense here to call object.__init__ at all, just remove that line.

---

Apart from that, everything works fine (except use %s instead of %d ).

Testing:

>>> baby = key('radan', 20)
>>> baby.somefunction()
yay the name is radan

Answer 3

Your code contains several errors:

class key(object):
    def __init__(self, name, age): # where's your age?
        self.name = name  # no need to call object.__init__
        self.age = age    # there is no such thing called "this", use self

    def somefunction(self):
        print "yay the name is %s" % self.name  # use %s as the comment says

baby = key('radan', 20)
baby.somefunction()

output:

>>> baby = key('radan', 20)
>>> baby.somefunction()
yay the name is radan