Dataclasses.asdict. Example of using asdict() on. Dataclasses.asdict

 
 Example of using asdict() onDataclasses.asdict asdict() は dataclass を渡すとそれを dict に変換して返してくれる関数です。 フィールドの値が dataclass の場合や、フィールドの値が dict / list / tuple でその中に dataclass が含まれる場合は再帰

; Here's another way which allows you to have fields without a leading underscore: from dataclasses import dataclass @dataclass class Person: name: str = property @name def name (self) -> str: return self. deepcopy(). Here is small example: import dataclasses from typing import Optional @dataclasses. However, in dataclasses we can modify them. 7, provides a way to create data classes in a simpler manner without the need to write methods. from dataclasses import dataclass @dataclass class Position: name: str lon: float = 0. It works perfectly, even for classes that have other dataclasses or lists of them as members. g. deepcopy(). First, we encode the dataclass into a python dictionary rather than a JSON. Currently when you call asdict or astuple on a dataclass, anything it contains that isn’t another dataclass, a list, a dict or a tuple/namedtuple gets thrown to deepcopy. dataclassy. A field is defined as class variable that has a type annotation. s # 'text' asdict(x) # {'i': 42} python; python-3. dataclasses, dicts, lists, and tuples are recursed into. asdict(res) True Is there something I'm misunderstanding regarding the implementation of the equality operator with dataclasses? Thanks. dataclasses. MISSING¶. dataclass class Foo: attr_1: str attr_2: Optional[int] = None attr_3: Optional[str] = None def combine_with_other(self, other: "Foo") -> "Foo":. field (default_factory=int) word : str = dataclasses. Static[]:Dataclasses are more of a replacement for NamedTuples, then dictionaries. If you don't want that, use vars instead. This is interesting, we can serialise data, but we cannot reverse this operation with the standard library. 如果你使用过. This uses an external library dataclass-wizard, which is a JSON serialization framework built on top of dataclasses. You can use the asdict function from dataclasses rather than __dict__ to make sure you have no side effects. asdict has keyword argument dict_factory which allows you to handle your data there: from dataclasses import dataclass, asdict from enum import Enum @dataclass class Foobar: name: str template: "FoobarEnum" class FoobarEnum (Enum): FIRST = "foobar" SECOND = "baz" def custom_asdict_factory. asdict和dataclasses. Each dataclass is converted to a dict of its fields, as name: value pairs. _name @name. Each dataclass is converted to a dict of its fields, as name: value pairs. データクラス obj を (ファクトリ関数 dict_factory を使い) 辞書に変換します。 それぞれのデータクラスは、 name: value という組になっている、フィールドの辞書に変換されます。 データクラス、辞書、リスト、タプ. Secure your code as it's written. asdict (obj, *, dict_factory = dict) ¶ Converts the dataclass obj to a dict (by using the factory function dict_factory). asdict for serialization. asdict (obj, *, dict_factory = dict) ¶ Converts the dataclass obj to a dict (by using the factory function dict_factory). is_dataclass(obj): raise TypeError("_asdict() should. I think you want: from dataclasses import dataclass, asdict @dataclass class TestClass: floatA: float intA: int floatB: float def asdict (self): return asdict (self) test = TestClass ( [0. Other objects are copied with copy. In the interests of convenience and also so that data classes can be used as is, the Dataclass Wizard library provides the helper functions fromlist and fromdict for de-serialization, and asdict for serialization. asdict. Кожен клас даних перетворюється на диктофон своїх полів у вигляді пар «ім’я: значення. It will accept unknown fields and not-valid types, it works only with the item getting [ ] syntax, and not with the dotted. It helps reduce some boilerplate code. loading data Reuse in args / kwargs of function declarations, e. For example, any extra fields present on a Pydantic dataclass using extra='allow' are omitted when the dataclass is print ed. 🎉. Using properties in dataclasses actually has a curious effect, as @James also pointed out. I am using the data from the League of Legends API to learn Python, JSON, and Data Classes. dataclasses, dicts, lists, and tuples are recursed into. Each dataclass is converted to a dict of its fields, as name: value pairs. dataclasses, dicts, lists, and tuples are recursed into. asdict before calling the cached function and re-assemble the dataclass later: from dataclasses import asdict , dataclass from typing import Dict import streamlit as st @ dataclass ( frozen = True , eq = True ) # hashable class Data : foo : str @ st . 54916ee 100644 --- a/dataclasses. Example of using asdict() on. 12. config_is_dataclass_instance. dataclass class myClass: item1: str item2: mySubClass # We need a __post_init__ method here because otherwise # item2 will contain a python. is_data_class_instance is defined in the source for 3. orm. @dataclass class MyDataClass: field0: int = 0 field1: int = 0 # --- Some other attribute that shouldn't be considered as _fields_ of the class attr0: int = 0 attr1: int = 0. The answer is: dataclasses. asdict(obj) (as pointed out by this answer) which returns a dictionary from field name to field value. Pydantic’s arena is data parsing and sanitization, while. ) Since creating this library, I've discovered. Other objects are copied with copy. py, included in the. Use. asdict, fields, replace and make_dataclass These four useful function come with the dataclasses module, let’s see what functionality they can add to our class. データクラス obj を (ファクトリ関数 dict_factory を使い) 辞書に変換します。 それぞれのデータクラスは、 name: value という組になっている、フィールドの辞書に変換されます。 データクラス、辞書、リスト、タプ. 7. Dataclasses asdict/astuple speed tests ----- Python v3. Then, the. asdict() on each, such as below. It helps reduce some boilerplate code. The dataclass decorator is used to automatically generate special methods to classes, including __str__ and __repr__. deepcopy(). 1 Answer. asDict (recursive = False) [source] ¶ Return as a dict. 6. Dataclass itself is. dataclasses. __init__ (x for x in data if x [1] is not None) example = Main () example_d = asdict (example, dict_factory=CustomDict) Edit: Based on @user2357112-supports. The next step would be to add a from_dog classmethod, something like this maybe: from dataclasses import dataclass, asdict @dataclass (frozen=True) class AngryDog (Dog): bite: bool = True @classmethod def from_dog (cls, dog: Dog, **kwargs): return cls (**asdict (dog), **kwargs) But following this pattern, you'll face a specific edge. Moreover, the attributes once defined cannot be modified in namedtuples. asdict ()` method to convert to a dictionary, but is there a way to easily convert a dict to a data class without eg looping through it. 简介. 7 (PEP 557). This is critical for most real-world programs that support several types. A tag already exists with the provided branch name. But the problem is that unlike BaseModel. asdict() will likely be better for composite dictionaries, such as ones with nested dataclasses, or values with mutable types such as dict or list. What the dataclasses module does is to make it easier to create data classes. In the interests of convenience and also so that data classes can be used as is, the Dataclass Wizard library provides the helper functions fromlist and fromdict for de-serialization, and asdict for serialization. Each dataclass is converted to a dict of its fields, as name: value pairs. This decorator is really just a code generator. asdict(obj, *, dict_factory=dict) ¶. One aspect of the feature however requires a workaround when. dataclasses, dicts, lists, and tuples are recursed into. Secure your code as it's written. Here's a suggested starting point (will probably need tweaking): from dataclasses import dataclass, asdict @dataclass class DataclassAsDictMixin: def asdict (self): d. astuple我们可以把数据类实例中的数据转换成字典或者元组:. Each dataclass is converted to a tuple of its field values. It also exposes useful mixin classes which make it easier to work with YAML/JSON files, as. asdict(foo) to return with the "$1" etc. Each dataclass is converted to a dict of its fields, as name: value pairs. ex. As hinted in the comments, the _data_cls attribute could be removed, assuming that it's being used for type hinting purposes. My question was about how to remove attributes from a dataclasses. Share. items (): do_stuff (key, value) Share. 11 and on the main CPython branch on Github. Improve this answer. Each dataclass is converted to a dict of its fields, as name: value pairs. 3f} ч. If they aren't then the classes won't. asdict (instance, *, dict_factory=dict) ¶ Converts the dataclass instance to a dict (by using the factory function dict_factory). This makes data classes a convenient way to create simple classes that. from dataclasses import dataclass, asdict @dataclass class MyDataClass: ''' description of the dataclass ''' a: int b: int # create instance c = MyDataClass (100, 200) print (c) # turn into a dict d = asdict (c) print (d) But i am trying to do the reverse process: dict -> dataclass. Whether this is desirable or not doesn’t really matter as changing it now will probably break things and is not my goal here. That's easy enough with dataclasses. dataclass class B: a: A # we can make a recursive structure a1 = A () b1 = B (a1) a1. Citation needed. unit_price * self. This is documented in PEP-557 Dataclasses, under inheritance: When the Data Class is being created by the @dataclass decorator, it looks through all of the class's base classes in reverse MRO (that is, starting at object) and, for each Data Class that it finds, adds the fields from that base class to an ordered mapping of fields. As an example I use this to model the response of an API and serialize this response to dict before serializing it to json. I think the problem is that asdict is recursive but doesn't give you access to the steps in between. The solution for Python 3. Each dataclass is converted to a dict of its fields, as name: value pairs. I can convert a dict to a namedtuple with something like. format (self=self) However, I think you are on the right track with a dataclass as this could make your code a lot simpler:It uses a slightly altered (and somewhat more effective) version of dataclasses. Use dataclasses. Currently when you call asdict or astuple on a dataclass, anything it contains that isn’t another dataclass, a list, a dict or a tuple/namedtuple gets thrown to deepcopy. 0. The ItemAdapter class is a wrapper for data container objects, providing a common interface to handle objects of different types in an uniform manner, regardless of their underlying implementation. asdict (inst, recurse: bool=True, filter: __class__=None, dict_factory: , retain_collection_types: bool=False) retain_collection_types : only meaningful if recurse is True. Done for the day, or are we? Dataclasses are slow1. I know that I can get all fields using dataclasses. dataclasses. dataclasses, dicts, lists, and tuples are recursed into. Specifying dict_factory as an argument to dataclasses. name) Then loop as usual: for key, value in obj. deepcopy(). Dataclass conversion may be added to any Declarative class either by adding the MappedAsDataclass mixin to a DeclarativeBase class hierarchy, or for decorator. asdict Unfortunately, astuple itself is not suitable (as it recurses, unpacking nested dataclasses and structures), while asdict (followed by a . The following are 30 code examples of dataclasses. 9,0. If you are into type hints in your Python code, they really come into play. Basically I need following. Convert dict to dataclass : r/learnpython. dumps(dataclasses. asdict (instance, *, dict_factory=dict) ¶ Converts the dataclass instance to a dict (by using the factory function dict_factory). asdict (obj, *, dict_factory = dict) ¶ Converts the dataclass obj to a dict (by using the factory function dict_factory). I know you asked for a solution without libraries, but here's a clean way which actually looks Pythonic to me at least. Learn more about Teams2. Rationale There have been numerous attempts to define classes which exist primarily to store. An example of both these approaches is. message. from dataclasses import dataclass import dataclass_factory @dataclass class Book: title: str. Other objects are copied with copy. asdict or the __dict__ field, but that erases the type checking. 0 @dataclass class Capital(Position): country: str # add a new field after fields with. Speed. Improve this answer. class MyClass:. My application will decode the request from dict to object, I hope that the object can still be generated without every field is fill, and fill the empty filed with default value. This is because it does not appear that your object is really much of a collection:Data-Oriented Programming by Yehonathan Sharvit is a great book that gives a gentle introduction to the concept of data-oriented programming (DOP) as an alternative to good old object-oriented programming (OOP). 8. deepcopy (). It is the callers responsibility to know which class to. dataclasses. Hopefully this will lead you in the right direction, although I'm unsure about nested dataclasses. asdict() here, instead record in JSON a (safe) reference to the original dataclass. They always require me to set sub_orders. name: f for f in fields (schema)} for. asdict:. deepcopy(). asdict() とは dataclasses. # Python 3. Do not use dataclasses. In particular this. Data[T] 対応する要素をデータ型Tで型変換したのち、DataFrameまたはSeriesのデータに渡す。Seriesの場合、2番目以降の要素は存在していても無視される。Data[typing. Sharvit deconstructs the elements of complexity that sometimes seems inevitable with OOP and summarizes the. As a workaround, I have noticed that annotating the return value will succeed with mypy. quantity_on_hand item = InventoryItem ('hammers', 10. from __future__ import. These functions also work recursively, so there is full support for nested dataclasses – just as with the class inheritance approach. First, tuple vs namedtuple factories and then asdict()’s implementation. Whether this is desirable or not doesn’t really matter as changing it now will probably break things and is not my goal here. asdict which allows for a custom dict factory: so you might have a function that would create the full dictionary and then exclude the fields that should be left appart, and use instead dataclasses. Dataclasses allow for easy declaration of python classes. `float`, `int`, formerly `datetime`) and ignore the subclass (or selectively ignore it if it's a problem), for example changing _asdict_inner to something like this: if isinstance(obj, dict): new_keys = tuple((_asdict_inner. """ class DataClassField(models. jsonpickle is not safe because it stores references to arbitrary Python objects and passes in data to their constructors. There are several ways around this. 0 The goal is to be able to call the function based on the dataclass, i. asdict. . asdict (obj, *, dict_factory = dict) ¶ Converts the dataclass obj to a dict (by using the factory function dict_factory). Dataclasses in Python are classes that are decorated using a tool from the standard library. Closed. deepcopy(). Each dataclass is converted to a dict of its fields, as name: value pairs. _is_dataclass_instance = dataclasses. Python dataclasses is a module that provides a dataclass decorator that can transform a regular class into a rich class. So bound generic dataclasses may be deserialized, while unbound ones may not. The dataclasses module doesn't appear to have support for detecting default values in asdict(), however the dataclass-wizard library does -- via skip_defaults. dataclasses, dicts, lists, and tuples are recursed into. Example of using asdict() on. experimental_memo def process_data ( data : Dict [ str , str ]): return Data. Simple one is to do a __post_init__. asdict helper function doesn't offer a way to exclude fields with default or un-initialized values unfortunately -- however, the dataclass-wizard library does. dumps(). That is because under the hood it first calls the dataclasses. asdict (obj, *, dict_factory = dict) ¶ Converts the dataclass obj to a dict (by using the factory function dict_factory). from abc import ABCMeta, abstractmethod from dataclasses import asdict, dataclass @dataclass class Message (metaclass=ABCMeta): message_type: str def to_dict (self) . e. py This module provides a decorator and functions for automatically adding generated special method s such as__init__() and__repr__() to user-defined classes. Found it more straightforward than messing with metadata. Additionally, interaction with arbitrary types is supported, by implementing a pre-defined interface (see extending itemadapter ). asdict = dataclasses. properties. _asdict_inner() for how to do that right), and fails if x lacks a class. python dataclass asdict ignores attributes without type annotation. Quick poking around with instances of class defined this way (that is with both @dataclass decorator and inheriting from pydantic. They provide elegant syntax for creating mutable data holder objects. asdict (instance, *, dict_factory=dict) ¶ Converts the dataclass instance to a dict (by using the factory function dict_factory). for example, but I would like dataclasses. from dataclasses import dataclass, asdict from typing import Optional @dataclass class CSVData: SUPPLIER_AID: str = "" EAN: Optional[str] = None DESCRIPTION_SHORT: str = "". from dataclasses import dataclass @dataclass class Position: name: str lon: float = 0. I suppose it’s possible to construct _ATOMIC_TYPES from copy Something like: _ATOMIC_TYPES = { typ for typ, func in copy. deepcopy(). For example: To prove that this is indeed more efficient, I use the timeit module to compare against a similar approach with dataclasses. 1. Update dataclasses. asdict and creating a custom __str__ method. deepcopy(). asdict (obj, *, dict_factory = dict) ¶ Converts the dataclass obj to a dict (by using the factory function dict_factory). Other objects are copied with copy. asdict (obj, *, dict_factory = dict) ¶ Перетворює клас даних obj на dict (за допомогою фабричної функції dict_factory). dataclasses, dicts, lists, and tuples are recursed into. Example of using asdict() on. _name = value def __post_init__ (self) -> None: if isinstance. 9+ from dataclasses import. 'abc-1234', 'def-5678', 'ghi-9123', ] Now the second thing we need to do is to infer the application default credentials and create the service for Google Drive. Pass the dictionary to the json. asdict (obj, *, dict_factory=dict) ¶ Converts the dataclass obj to a dict (by using the factory function dict_factory). Introduced in Python 3. Example of using asdict() on. We've assigned to a value on an instance. From StackOverflow pydantic tag info. asdict (obj, *, dict_factory = dict) ¶ Converts the dataclass obj to a dict (by using the factory function dict_factory). def get_message (self) -> str: return self. g. @classmethod @synchronized (lock) def foo (cls): pass. Whilst NamedTuples are designed to be immutable, dataclasses can offer that functionality by setting frozen=True in the decorator, but provide much more flexibility overall. Каждый dataclass преобразуется в dict его полей в виде пар name: value. {"payload":{"allShortcutsEnabled":false,"fileTree":{"Lib":{"items":[{"name":"__phello__","path":"Lib/__phello__","contentType":"directory"},{"name":"asyncio","path. dataclasses. dataclasses. dataclasses, dicts, lists, and tuples are recursed into. astuple and dataclasses. s(frozen = True) class FrozenBar(Bar): pass # Three instances: # - Bar. Python Dict vs Asdict. Therefo… The inverse of dataclasses. So it's easy to use with a document database like. Define DataClassField. Python dataclasses are a powerful feature that allow you to refactor and write cleaner code. _asdict(obj) def _asdict(self, obj, *, dict_factory=dict): if not dataclasses. Other objects are copied with copy. dataclasses, dicts, lists, and tuples are recursed into. Dict to dataclass makes it easy to convert dictionaries to instances of dataclasses. InitVarで定義したクラス変数はフィールドとは認識されずインスタンスには保持されません。Pydantic dataclasses support extra configuration to ignore, forbid, or allow extra fields passed to the initializer. @dataclasses. message_id) dataclasses. asdict ()` method to convert to a dictionary, but is there a way to easily convert a dict to a data class without eg looping through it. With such references I can get jsonpickle to reference internal Python data structures and create and execute. dataclasses, dicts, lists, and tuples are recursed into. Example of using asdict() on. g. asdict each time I instantiate, like: What I have tried. For example:from typing import List from dataclasses import dataclass, field, asdict @da… Why did the developers add deepcopy to asdict, but did not add it to _field_init (for safer creation of default values via default_factory)? from typing import List from dataclasses import dataclass, field, asdict @dataclass class Viewer: Name: str. dataclasses. from dataclasses import dataclass, field @ dataclass class User: username: str email:. The dataclass decorator is used to automatically generate special methods to classes, including __str__ and __repr__. message_id = str (self. 0 lat: float = 0. In a. We have arrived at what I call modern attrs: from attrs import define @define class Point: x: int y: int. Other objects are copied with copy. asdict() method and send to a (sanely constructed function that takes arguments and therefore is useful even without your favorite object of the day, dataclasses) with **kw syntax. The new attrs import namespace currently simply re-imports (almost) all symbols from the old attr one that is not going anywhere. deepcopy(). My use case was lots of models that I'd like to store in an easy-to-serialize and type-hinted way, but with the possibility of omitting elements (without having any default values). For more information and discussion see. dataclasses. In other word decorators allow you to write less lines of codes for getting very same result. To convert a Python dataclass into a dictionary, you can use the asdict function provided by the dataclasses module. dataclasses. Each dataclass is converted to a dict of its fields, as name: value pairs. Python. 4. asdict is defined by the dataclasses library and returns a dictionary of the dataclass fields. asdict() is taken from the dataclasses package, it builds a complete dictionary from your dataclass. Sometimes, a dataclass has itself a dictionary as field. format() in oder to unpack the class attributes. To prove that this is indeed more efficient, I use the timeit module to compare against a similar approach with dataclasses. asdict to generate dictionaries. The dataclasses module doesn't appear to have support for detecting default values in asdict(), however the dataclass-wizard library does -- via skip_defaults argument. However, some default behavior of stdlib dataclasses may prevail. Each dataclass is converted to a tuple of its field values. astuple. name, getattr (self, field. In short, dataclassy is a library for. This is a reasonable best practice to follow, but in the particular case of dataclasses, it doesn't make any sense. deepcopy(). dataclasses are decorators and need to be added in the python code above the class definition to use them. For example, consider. You can use the dataclasses. tuple() takes an iterable as its only argument and exhausts it while building a new object. Example of using asdict() on. dataclasses模块中提供了一些常用函数供我们处理数据类。. Using type hints and an optional default value. I can convert a dict to a namedtuple with something like. dataclasses, dicts, lists, and tuples are recursed into. But it's really not a good solution. Just use a Python property in your class definition: from dataclasses import dataclass @dataclass class SampleInput: uuid: str date: str requestType: str @property def cacheKey (self): return f" {self. You can use dataclasses. dataclasses. dataclasses. asdict(myinstance, dict_factory=attribute_excluder) - but one would have to remember which dict. MessageSegment. if you have code that uses tuple. dataclasses. Note also: I've needed to swap the order of the fields, so that. Currently when you call asdict or astuple on a dataclass, anything it contains that isn’t another dataclass, a list, a dict or a tuple/namedtuple gets thrown to deepcopy. Let’s say we create a. from dataclasses import dataclass, asdict @dataclass class MyDataClass: ''' description of the dataclass ''' a: int b: int # create instance c = MyDataClass (100, 200) print (c) # turn into a dict d = asdict (c) print (d) But i am trying to do the reverse process: dict -> dataclass. dataclass class A: a: str b: int @dataclasses. I don't know how internally dataclasses work, but when I print asdict I get an empty dictionary. For example: python Copy. asdict(instance, *, dict_factory=dict) Converts the dataclass instance to a dict. def _asdict_inner(obj, dict_factory): if _is_dataclass_instance(obj): result = [] for f in fields(obj): value = _asdict_inner(getattr(obj, f. dataclasses, dicts, lists, and tuples are recursed into. In this article, we'll see how to take advantage of this module to quickly create new classes that already come not only with __init__ , but several other methods already implemented so we don. The example below should work for Python 3. There are a lot of good ones out there, but for this purpose I might suggest dataclass-wizard. item. See documentation for more details. asdict (obj, *, dict_factory = dict) ¶ Перетворює клас даних obj на dict (за допомогою фабричної функції dict_factory). """ data = asdict (schema) if data is None else data cleaned = {} fields_ = {f. I have the following dataclass: @dataclass class Image: content_type: str data: bytes = b'' id: str = "" upload_date: datetime = None size: int = 0 def to_dict(self. dataclasses, dicts, lists, and tuples are recursed into. asdict (obj, *, dict_factory = dict) ¶ Converts the dataclass obj to a dict (by using the factory function dict_factory). It was or. Fortunately, if you don't need the signature of the __init__ method to reflect the fields and their defaults, like the classes rendered by calling dataclass, this. dataclasses, dicts, lists, and tuples are recursed into. Each dataclass is converted to a dict of its fields, as name: value pairs. . In the interests of convenience and also so that data classes can be used as is, the Dataclass Wizard library provides the helper functions fromlist and fromdict for de-serialization, and asdict for serialization. 5], [1,2,3], [0. bool. )dataclasses. append (b1) # stringify supports recursion. How can I use asdict() method inside . def dump_dataclass(schema: type, data: Optional [Dict] = None) -> Dict: """Dump a dictionary of data with a given dataclass dump functions If the data is not given, the schema object is assumed to be an instance of a dataclass. asdict. py @@ -1019,7 +1019,7 @@ def _asdict_inner(obj, dict_factory): result. fields → Returns all the fields of the data class instance with their type,etcdataclasses. Example of using asdict() on. """ return _report_to_json(self) @classmethod def _from_json(cls: Type[_R], reportdict: Dict[str, object]) -> _R: """Create either a TestReport or CollectReport, depending on the calling class. asdict() mishandles dataclass instance attributes that are instances of subclassed typing. 7. from dataclasses import dataclass @dataclass(init=False) class A: a: str b: int def __init__(self, a: str, b: int, **therest): self. This is how the dataclass. 14. dataclasses, dicts, lists, and tuples are recursed into. Other objects are copied with copy. asdict(). cpython/dataclasses. Looks like there's a lot of interest in fixing this! We've already had two PRs filed over at mypy and one over at typeshed, so I think we probably don't need. Connect and share knowledge within a single location that is structured and easy to search. dataclasses. Python Python Dataclass. asdict (obj, *, dict_factory=dict) ¶ Converts the dataclass obj to a dict (by using the factory function dict_factory). Other objects are copied with copy. dataclasses, dicts, lists, and tuples are recursed into. This feature is supported with the dataclasses feature. dataclasses, dicts, lists, and tuples are recursed into. I choose one of the attributes to be dependent on the other, e. 9, seems to be declare the dataclasses this way, so that all fields in the subclass have default values: from abc import ABC from dataclasses import dataclass, asdict from typing import Optional @dataclass class Mongodata (ABC): _id: Optional [int] = None def __getdict__ (self): result = asdict (self). a = a self. So that instead of this: So that instead of this: from dataclasses import dataclass, asdict @dataclass class InfoMessage(): training_type: str duration: float distance: float message = 'Training type: {}; Duration: {:. asdict(). Note: the following should work in Python 3. Each dataclass is converted to a dict of its fields, as name: value pairs. append((f. The dataclasses module seems to mostly assume that you'll be happy making a new object. 1 is to add the following lines to my module: import dataclasses dataclasses. asdict for serialization.