Type hints in namedtuple

Consider following piece of code: from collections import namedtuple point = namedtuple("Point", ("x:int", "y:int")) The Code above is just a way to demonstrate as to what I am trying to...

How do I avoid the "self.x = x; self.y = y; self.z = z" pattern in __init__?

I see patterns like def __init__(self, x, y, z): ... self.x = x self.y = y self.z = z ... quite frequently, often with a lot more parameters. Is there a good way to avoid...

What are data classes and how are they different from common classes?

With PEP 557 data classes are introduced into python standard library. They make use of the @dataclass decorator and they are supposed to be "mutable namedtuples with default" but I'm not really...

Dataclasses and property decorator

I've been reading up on Python 3.7's dataclass as an alternative to namedtuples (what I typically use when having to group data in a structure). I was wondering if dataclass is compatible with the...

Make the Python json encoder support Python's new dataclasses

Starting with Python 3.7, there is something called a dataclass: from dataclasses import dataclass @dataclass class Foo: x: str However, the following fails: >>> import json >>> foo =...

Creating nested dataclass objects in Python

I have a dataclass object that has nested dataclass objects in it. However, when I create the main object, the nested objects turn into a dictionary: @dataclass class One: f_one:...

Class inheritance in Python 3.7 dataclasses

I'm currently trying my hands on the new dataclass constructions introduced in Python 3.7. I am currently stuck on trying to do some inheritance of a parent class. It looks like the order of the...

Data Classes vs typing.NamedTuple primary use cases

Long story short PEP-557 introduced data classes into Python standard library, that basically can fill the same role as collections.namedtuple and typing.NamedTuple. And now I'm wondering how to...

Python dataclass from a nested dict

The standard library in 3.7 can recursively convert a dataclass into a dict (example from the docs): from dataclasses import dataclass, asdict from typing import List @dataclass class Point: ...

How can I show the code that is generated when using @dataclass class decorator?

Python 3.7 introduces the dataclasses module that contains a @dataclass decorator. This decorator can generate class functions. How can I print these generated functions?

type hint for an instance of a non specific dataclass

I have a function that accepts an instance of any dataclass. what would be an appropriate type hint for it ? haven't found something official in the python documentation this is what I have been...

python3 dataclass with **kwargs(asterisk)

Currently I used DTO(Data Transfer Object) like this. class Test1: def __init__(self, user_id: int = None, body: str = None): self.user_id = user_id self.body...

How to declare an array or a list in a Python @dataclass?

How can I declare an array (or at least list) in @dataclass? A something like below: from dataclasses import dataclass @dataclass class Test(): my_array: Array[ChildType]

How can I set an attribute in a frozen dataclass custom __init__ method?

I'm trying to build a @dataclass that defines a schema but is not actually instantiated with the given members. (Basically, I'm hijacking the convenient @dataclass syntax for other purposes). This...

Easiest way to copy all fields from one dataclass instance to another?

Let's assume you have defined a Python dataclass: @dataclass class Marker: a: float b: float = 1.0 What's the easiest way to copy the values from an instance marker_a to another instance...

Python frozen dataclass, allow changing of attribute via method

Suppose I have a dataclass: @dataclass(frozen=True) class Foo: id: str name: str I want this to be immutable (hence the frozen=True), such that foo.id = bar and foo.name = baz fail. But,...

Better way to iterate over python dataclass keys and values?

I have two dataclasses, Route and Factors. Route contains a value and three copies of Factors. Route does not know how many variables factors contains. I want to get the name of these variables,...

Python: Circular dependency of dataclasses / Forward variable declaration?

So, I have these two dataclasses in a file: @dataclass class A: children: List[B] @dataclass class B: parent: A , which are possible with the use of the __future__.annotations...

Using hash for identity on Python dataclasses

I have the following Filer entity (in the domain-driven design sense). from dataclasses import dataclass, field @dataclass class Address: street: str city: str state: str zipcode:...

Can I have an optional parameter in dataclasses that is omitted when transformed to dict?

I wish to perform static type checking (pylance in vscode) on some dictionaries. The "tricky" part is the I want some of the parameters to be optional and not show up at all in the dictionary....

Pretty-print dataclasses prettier

Python Data Classes instances also include a string representation method, but its result isn't really sufficient for pretty printing purposes when classes have more than a few fields and/or...

Im trying to build mediapipe on my jetson nano

So Im trying to build a mediapipe whl file for my jetson nano by following this guide https://github.com/jiuqiant/mediapipe_python_aarch64 I am successful on building it with my raspberry pi 4. By...

Python Singleton Dataclass

I have a class like this: from __future__ import annotations import os from dataclasses import dataclass @dataclass(frozen=True) class Config: name: str age: str @staticmethod def init()...

Combining a descriptor class with dataclass and field

I am using a dataclass and field to pass in a default value. When an argument is provided I want to validate it using a descriptor class. Is there any way to utilize the benefits of field (repr,...

Using SQLAlchemy 1.4 classical / imperative mapping style?

I am using the clean architecture & TDD development method in my Python project. Updating from SQLAlchemy 1.3 to SQLAlchemy 1.4 broke the ability to test against an in-memory Postgres DB, and I...

How to get an abstract dataclass to pass mypy?

mypy v0.910 rejects abstract dataclasses in Python 3.9. Here's the Minimal Reproducible Example: from abc import ABC, abstractmethod from dataclasses import dataclass @dataclass class...

How to build a self-referencing model in Pydantic with dataclasses?

I am building an API using FastAPI and pydantic. As I follow DDD / clean architecture, which separates the definition of the model from the definition of the persistence layer, I use standard lib...

How do I convert a json file to a python class?

Consider this json file named h.json I want to convert this into a python dataclass. { "acc1":{ "email":"[email protected]", "password":"acc1", "name":"ACC1", ...

Avoiding type warning for lists of sortable elements

I've got a list of elements of a dataclass X (marked order=True) and pass them to max(). I get a type checking warning in my IDE: Expected type 'Iterable' (matched generic type...

How to override names of dataclasses attributes in Python?

I am using dataclass to parse (HTTP request/response) JSON objects and today I came across a problem that requires transformation/alias attribute names within my classes. from dataclasses import...