comparing types between a class and a dictionary-CodePudding

I am working with dictionaries and classes and I want to check that the dictionaries and the classes have the same field types.

For example, I have a dataclass of this form

@dataclasses.dataclass
class FlatDataclass:
    first_field: str
    second_field: int

and I have a dictionary of this form

my_dict={first_field:"a_string", second_field:"5"}

I want to check that the values of the dictionary have the right type for the class.

So far I can get the types for the dictionary, from this:

dct_value_types = list(type(x).__name__ for x in list(dct.values()))

returns ['str', 'str']

however

[f.type for f in dataclasses.fields(klass)]

[<class 'str'>, <class 'int'>]

rather than ['str', 'str'], so I can't compare them.

How would you get the types in a way you can compare them?

CodePudding user response：

Either you do this

[f.type.__name__ for f in dataclasses.fields(klass)]

Or you do this

dct_value_types = list(type(x) for x in list(dct.values()))

Notice that I added or removed __name__ here, so both type checks should either have it or not

CodePudding user response：

You can use this function that checks if all the fields in the dataclass are present in a given dictionary and have same type -

def has_all_fields(d, custom_class):
    return all(field.name in d and isinstance(d[field.name], field.type) for field in dataclasses.fields(custom_class))

@dataclasses.dataclass
class FlatDataclass:
    first_field: str
    second_field: int

my_dict={"first_field":"a_string", "second_field":5}
print(has_all_fields(my_dict, FlatDataclass))

Output:

True

Note that this would still return True if dictionary has more fields than what the dataclass does.