CODEWITHSUNDEEP
pythonmember
prosseek
prosseek

Reputation: 191179

How to check the values in a instance with Python?

I have a python class/object as follows.

class Hello:
    def __init__(self):
        self.x = None
        self.y = None
        self.z = None


h = Hello()
h.x = 10
h.y = 20
# h.z is not set

I need to check if all the member variables are set (not None). How can I do that automatically? 

for value in ??memeber variables in h??:
    if value == None:
        print 'value is not set'

Upvotes: 0

Views: 245

Answers (2)

S.Lott
S.Lott

Reputation: 392050

I need to check if all the member variables are set (not None).

Why?

You need the member variables in order to do some processing in the class.

class Hello:
    def __init__(self):
        self.x = None
        self.y = None
        self.z = None
    def some_processing( self ):
        assert all( self.x is not None, self.y is not None, self.z is not None )
        # Now do the processing.

Upvotes: 0

Lie Ryan
Lie Ryan

Reputation: 64943

class Hello(object):
    def __init__(self):
        self.x = None
        self.y = None
        self.z = None
    def is_all_set(self):
        return all(getattr(self, attr) is not None for attr in self.__dict__)

though, as @delnan said, you should prefer to make it impossible for the class to always be in a valid state (this is referred to as preserving "class invariants")

Upvotes: 3

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