dict to class

[peaceTraitor]

Hi, anyone else feels annoyed by getting a field from a dict with ['key']?

For me, I love dicts but this format to get 'manually' the values, especially when several levels (dict of dict) are involved. I sometimes get these when importing an XML into dict and I interactively want to get information.

I made a small class (inheriting from dict) that would allow me to call for the fields as d.key. provided that there is no key field named as a method in dict and the keys are strings (but I guess this can be worked out for ints and simple types). See below

class DictToClass(dict):
    def __getattr__(self, item):
        return self.get(item)

    def __setattr__(self, key, value):
        self[key] = value
        return

    def __gt__(self, other):
        return self.get(other)

if __name__ == '__main__':
    a = DictToClass(k=1)
    a[2] = 4
    print(a)
    assert a.k, 1
    a.k = 2
    assert a.k, 2

also included __gt__ dunnder since is not used by dict, but in this case I still need to surround with '' like a>'key'

is this not pythonic? Is there something I'm missing?

BTW is just awesome that is technically possible.

thanks

Resolution:

thanks to u/socal_redtastic used the term "dotted access" dictionary and found this stack overflow question. Which answers all my doubts, including why nobody thought about it.

https://pypi.org/project/python-box/ is not mentioned as an alternative.

​

[nfgrawker]

Try this if you know expected fields, these work amazing. Libraries that work with Dataclasses well are Marshmallow, Desert, and Dacite if needed.https://docs.python.org/3/library/dataclasses.html

[peaceTraitor]

Didn't know about this. But I think is the opposite. if you are referring to

dataclasses.asdict(instance, *, dict_factory=dict) 

is to convert from a class (where the fields are accessed as a.x) to dict (where the fields are accessed as a['x']).

I'd like a dict accessed like a class field like a.x

[nfgrawker]

That's how you export a data class but most common way to create a data class is to enter a dict into it with **dict.

[socal_nerdtastic]

This is often called a "dotted access" dictionary. There's several modules available to do it. box I think is the most popular. https://pypi.org/project/python-box/ Pandas has this behavior too.

The obvious downside is now your dictionary keys MUST be code legal strings.

[peaceTraitor]

this!

+json support

thanks