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up vote 8 down vote favorite
1

I need to make a bunch of class variables and I would like to do it by looping through a list like that:

vars=('tx','ty','tz') #plus plenty more

class Foo():
    for v in vars:
        setattr(no_idea_what_should_go_here,v,0)

is it possible? I don't want to make them for an instance (using self in the __init__) but as class variables.

share|improve this question
    
Why not to hold them in dict? –  DrTyrsa Nov 29 '11 at 8:15
    
Do you want to share theses variables between different instances? –  luc Nov 29 '11 at 8:17
    
not sure. most likely. the requirement comes from an API and I don't know how they are used in there. –  pawel Nov 29 '11 at 8:28

2 Answers 2

up vote 8 down vote accepted

You can run the insertion code immediately after a class is created:

class Foo():
     ...

vars=('tx', 'ty', 'tz')  # plus plenty more
for v in vars:
    setattr(Foo, v, 0)
share|improve this answer
    
ah. that's cool. I will give it a go and see if the API I work with can handle that. thanks mate! –  pawel Nov 29 '11 at 8:28
up vote 1 down vote

If for any reason you can't use Raymond's answer of setting them up after the class creation then perhaps you could use a metaclass:

class MetaFoo(type):
    def __new__(mcs, classname, bases, dictionary):
        for name in dictionary.get('_extra_vars', ()):
            dictionary[name] = 0
        return type.__new__(mcs, classname, bases, dictionary)

class Foo(): # For python 3.x use 'class Foo(metaclass=MetaFoo):'
    __metaclass__=MetaFoo # For Python 2.x only
    _extra_vars = 'tx ty tz'.split()
share|improve this answer
1  
name in for loop clashes with __new__ argument –  uszywieloryba Feb 21 '13 at 12:05
    
@UszyWieloryba thanks, corrected –  Duncan Feb 21 '13 at 14:30

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