在同一个类中列出静态属性时，Python中的NameError

Question

I have the following python class:

class list_stuff:    
        A = 'a'
        B = 'b'
        C = 'c'
        stufflist = [v for k,v in list_stuff.__dict__.items() if not k.startswith("__")]

But it shows a NameError saying undefined variable list_stuff .

According to this , it should work.

I also tried with:

list_stuff().__dict__.items()

But still same error. What am I missing here?

Answer 1

In Python you cannot reference the class in the class body. The issue I see here is that you are referring to the class list_stuff within the class definition. To resolve simply move that line outside the class:

class list_stuff:    
    A = 'a'
    B = 'b'
    C = 'c'

stufflist = [v for k,v in list_stuff.__dict__.items() if not k.startswith("__")]

Here is the documentation on classes

Answer 2

I ended up doing this:

class list_stuff:    
    A = 'a'
    B = 'b'
    C = 'c'

    @classmethod
    def stufflist(cls):
        return [v for k,v in cls.list_stuff.__dict__.items() if not k.startswith("__")]

which has the same effect as my original intent.

Thanks all for quick replies.

Answer 3

The problem seems to be the indentation, as you are essentially calling the class from within.

Try this:

class list_stuff:    
    A = 'a'
    B = 'b'
    C = 'c'
stufflist = [v for k,v in list_stuff.__dict__.items() if not k.startswith("__")]

Answer 4

You can create a method that would generate the list attribute you wish. First you will need to generate an instance of that class, before running the get_list() method.

class list_stuff():
    A = 'a'
    B = 'b'
    C = 'c'  

def get_list(self):
    self.thelist = [v for k,v in list_stuff.__dict__.items() if not k.startswith("__")]
    return self.thelist

list_a = list_stuff()
print list_a.get_list()
print list_a.thelistenter code here

This is what it returns:

['a', 'b', 'c', <function get_list at 0x7f07d6c63668>]
['a', 'b', 'c', <function get_list at 0x7f07d6c63668>]