Update an object with a dictionary

[Paolo Corti]

Hi
is it possible to update an object with a dictionary?

I tried something like this:
myobject.save(force_update=True, **my_dict)

getting an error, though:
TypeError at ...
save() got an unexpected keyword argument 'myfieldname'

I wouldn't like to iterate the dictionary, neither to delete and
create the object again using the dictionary, is there a best
approach?

thanks
Paolo

[Daniel Roseman]

The error is in passing the dictionary to the save() method. If you've
got an existing object and you want to update it, this will work:
my_object.__dict__.update(my_dict)
myobject.save()
--
DR.

[Kevin Teague]

.save() is only for persisting the object to disk, not for modifying
objects. To update any Python object from a dictionary is as easy as:

for k,v in d.items(): setattr(myobject, k, v)

[Paolo Corti]

>
> .save() is only for persisting the object to disk, not for modifying
> objects. To update any Python object from a dictionary is as easy as:
>
> for k,v in d.items(): setattr(myobject, k, v)

this is also what i came to.
But curious to try the Daniel's approach, will let you know
best regards

[Kevin Teague]

__dict__ is an attribute of every Python object. It's typically only
an internal detail, and generally not accessed directly. One area
where __dict__ modification would differ from attribute access is with
an attribute that's a property. Modifying the __dict__ would ignore
the property getter/setter code, where as modifying the attribute will
still invoke those methods. In other words, __dict__ manipulation
breaks encapsulation ... although in rare cases this is what you want
to do!


>>> class Foo(object): pass
...
>>> f = Foo()
>>> f.__dict__
{}
>>> f.cat = 'dog'
>>> f.__dict__
{'cat': 'dog'}
>>> f.__dict__['cow'] = 'moo'
>>> f.cow
'moo'

[Alex Gaynor]

Technically it's not on every Python object, any object that defines __slots__ won't have it.

Alex

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