Question

I m developing in Python using PyDev in Eclipse, and some of my code generates errors in the code analysis tool. Specifically:

class Group(object):
    def key(self, k):
        class Subkey(object):
            def __enter__(s):
                self._settings.beginGroup(k)
                return self

            def __exit__(s, type, value, tb):
                self._settings.endGroup()

         return Subkey()

Gives me a "Method __enter__- group should have self as first parameter" error, and a similar error for __exit__. Is there a way to solve this without assigning self to another variable and reusing the variable in the other method signatures?

Answer 1

You could disable that error in the preferences...

Window > Preferences > Pydev > Editor > Code Analysis > Others

Or refactor the code...

class Group(object):
    def key(self, k):
        outer_self = self
        class Subkey(object):
            def __enter__(self):
                outer_self._settings.beginGroup(k)
                return outer_self

            def __exit__(self, type, value, tb):
                outer_self._settings.endGroup()

         return Subkey()

What else do you expect? The error checks are there to help you. If you don t think they re legitimate errors, disable them or refactor the code.

In this case I d say refactor the code. It s more readable, as evidenced by King Radical s answer. He didn t understand that s was another self.

Answer 2

Using Ctrl+1 in a line with an error from PyDev will always bring you a fix which will allow you to ignore the PyDev error in the line. In this specific case, it ll allow you to ignore the error by adding #@NoSelf to the end of the line. Ctrl+1 is also useful when some unused import is needed and under other situations.

Answer 3

You can use a decorator:

class aClass:
        def __init__(self):       # instance-dependent method
        self.atribite1 = []
        self.atribute2 = 0 

        @staticmethod   
        def static():             # static method
        pass

The Built-in function used for this

Answer 4

It shouldn t be an error in the first place, as using "self" is only a widely-accepted convention. It should be a warning at most, in the sense of "are you sure you re using the class instance as the first argument?"

Answer 5

IMO this is a silly warning. the name "self" is only convention. I got the habit of using the name "_" to allow the member names to be more obvious,

class myClass( object ):
    def __init__( _, color, shape, weight ):
        _.color=color
        _.shape=shape
        _.weight=weight
...

and I get this warning all over my library of thousands of lines of code. So I ll be switching this warning off. Would be nice to be able to specify "for this project I use _ by convention"...

Answer 6

PyDev is telling you that Python class methods must have self as the first variable they receive, if they re going to access the class member variables. See: http://www.python.org/doc/faq/general/#why-must-self-be-used-explicitly-in-method-definitions-and-calls

Edit: It didn t initially occur to me that you might be using s instead of self, but in view of the other answers, that may be. However, if you re going to do that, you also need to use s as your variable in the method, rather than self.

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