Add attributes to object by init kwargs

Question

class Obj:
    def __init__(self, **kw):
        # code

obj = Obj(a=5, b=10)
print(obj.a, obj.b) # 5 10

Is there a proven solution to this task?

`self.__dict__.update(kw)`? See e.g. https://stackoverflow.com/q/8187082/3001761, and please research in the future. — jonrsharpe, Apr 22 '20 at 19:08
Does this answer your question? [How can you set class attributes from variable arguments (kwargs) in python](https://stackoverflow.com/questions/8187082/how-can-you-set-class-attributes-from-variable-arguments-kwargs-in-python) — wjandrea, Apr 22 '20 at 19:13
Just note that this is mostly an antipattern - there are very very few valid reasons to do this. — bruno desthuilliers, Apr 23 '20 at 06:49
@jonrsharpe that's only applicable to python 2, in py3 you get `AttributeError: 'mappingproxy' object has no attribute 'update'`. Please research in the future. ;) — Jonas Byström, Apr 23 '20 at 07:10
@JonasByström in Python 2.x this would be an old-style class, too — jonrsharpe, Apr 23 '20 at 07:12

score 2 · Answer 1 · edited Apr 23 '20 at 07:28

2

You can do the following to assign attributes passed in **kw:

class Obj:
    def __init__(self, **kw):
        # in case of python 2, the following line is: for k, v in kw.iteritems():
        for k, v in kw.items():
            setattr(self, k, v)

and then use the way you mentioned in your post:

obj = Obj(a=5, b=10)
print(obj.a, obj.b) # 5 10

edited Apr 23 '20 at 07:28

Jonas Byström

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answered Apr 23 '20 at 07:04

akazuko

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@jonas-bystrom your edit is wrong as you can see here ```Python 3.7.3 (default, Dec 13 2019, 19:58:14) [Clang 11.0.0 (clang-1100.0.33.17)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> k = {"a": "b"} >>> k.iter() Traceback (most recent call last): File "", line 1, in AttributeError: 'dict' object has no attribute 'iter' >>> k.items() dict_items([('a', 'b')])``` – akazuko Apr 23 '20 at 07:13
@jonas it's called *items* in Python 3, as was already commented in the post – jonrsharpe Apr 23 '20 at 07:14
1

Syntax error in brain, sorry bout that! `iteritems()` is not present in py3 however so retried my fix with the correct name and reversed the comment as op's question was about py3. – Jonas Byström Apr 23 '20 at 07:28

Add attributes to object by init kwargs

1 Answers1