Python function recursion within a class

Question

I made the below class.

class Message:

    def __init__(self, message):
        self.message = message
        self.__dict__.update(message)

    def dict_value_finder(self, field, partial_match=False):
        """It Takes a dict with nested lists and dicts,
        and searches all dicts for a key of the field
        provided and return the value(s) as a list.
        set partial_match = True to get partial matches.
        """
        fields_found = []

        for key, value in self.message.items():

            if field in key if partial_match else field == key:
                fields_found.append(value)
                print(key, value)

            elif isinstance(value, dict):
                results = dict_value_finder(value, field, partial_match)
                fields_found.extend(results)

            elif isinstance(value, list):
                for item in value:
                    if isinstance(item, dict):
                        more_results = dict_value_finder(item, field,
                                                         partial_match)
                        fields_found.extend(more_results)

        return fields_found

The function dict_value_finder would work outside the class as in:

def dict_value_finder(search_dict, field, partial_match=False):
    """Takes a dict with nested lists and dicts,
    and searches all dicts for a key of the field
    provided and return the value(s) as a list.
    set partial_match = True to get partial matches.
    """
    fields_found = []

    for key, value in search_dict.items():

        if field in key if partial_match else field == key:
            fields_found.append(value)
            print(key, value)

        elif isinstance(value, dict):
            results = dict_value_finder(value, field, partial_match)
            fields_found.extend(results)

        elif isinstance(value, list):
            for item in value:
                if isinstance(item, dict):
                    more_results = dict_value_finder(item, field,
                                                     partial_match)
                    fields_found.extend(more_results)

    return fields_found

But when I put it inside the class I get the error:

  File "<ipython-input-42-76ab838299bc>", line 23, in dict_value_finder
    results = dict_value_finder(value, field, partial_match)

NameError: name 'dict_value_finder' is not defined

I'm not sure How to add this function to a class given that it needs recursion.

You used self when referring to message but not when referring to dict_value_finder. Why? — DeepSpace
– DeepSpace, Commented Dec 5, 2018 at 11:10

Mehrdad Pedramfar · Accepted Answer · 2018-12-05 11:26:20Z

3

Change results = dict_value_finder(value, field, partial_match) to this:

results = self.dict_value_finder(value, field, partial_match)

and more_results = dict_value_finder(item, field,partial_match) to:

more_results = self.dict_value_finder(item, field,partial_match)

For accessing attributes of an instance of class we should use self.

For solving the question in comments:

def dict_value_finder(self, field, partial_match=False, search=None):

    fields_found = []

    search =  search or self.message

    for key, value in search.items():

        if field in key if partial_match else field == key:
            fields_found.append(value)
            print(key, value)

        elif isinstance(value, dict):
            results = self.dict_value_finder(field, partial_match, value)
            fields_found.extend(results)

        elif isinstance(value, list):
            for item in value:
                if isinstance(item, dict):
                    more_results = self.dict_value_finder(field,partial_match, item)
                    fields_found.extend(more_results)

    return fields_found

edited Dec 5, 2018 at 11:26

answered Dec 5, 2018 at 11:09

Mehrdad Pedramfar

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4 Comments

Blue Moon Over a year ago

TypeError: dict_value_finder() takes from 2 to 3 positional arguments but 4 were given

Blue Moon Over a year ago

it should not take self as first argument but either value or item

Mehrdad Pedramfar Over a year ago

This comes from the definition of your method def dict_value_finder(self, field, partial_match=False): you didn't define item or value there.

Blue Moon Over a year ago

item and value should replace self.message. How can I do that?

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