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Python3 AttributeError while setting properties using ** kwargs

Simply put, I understand why I can't set the property using a loop for

with **kwargs

like this:

class Person():
    def __init__(self, onevar, *args, **kwargs):
        self.onevar = onevar
        for k in kwargs:
            self.k = kwargs[k]
            print(k, self.k)   

def run():
    ryan = Person('test', 4, 5, 6, name='ryan', age='fifty')
    print(ryan.name)

def main():
    run()

if __name__=="__main__":
    main()

This returns the following:

AttributeError: 'Person' object has no attribute 'name'

Does anyone know why?

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2 answers


When you assign self.k

, you are not actually creating the named attribute k

, you are just creating the named attribute k

multiple times. If I understand what you are trying to do you need to replace

self.k = kwargs[k]

from



setattr(self, k, kwargs[k])

to achieve what you want.

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EDIT : @ tzaman's answer is better. Use setattr

as he suggests.

You expect to k

become a variable, but that won't work. However, you can expand the base object

in Python and set your variables using an internal property __dict__

.



You can also use iteritems()

to get the value directly.

class Person(object):
    def __init__(self, onevar, *args, **kwargs):
        self.onevar = onevar
        for k,v in kwargs.iteritems():
            self.__dict__[k] = v
            print(k, self.__dict__.get(k))
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