Questions tagged [python-attrs]
Use for questions about the third-party Python library for data classes
python-attrs
160
questions
3
votes
2
answers
286
views
How to mock an attr.ib validator
I have an attrs class:
@attr.s
class Example:
my_int = attr.ib(validator=attr.validator.instance_of(MyComplexType))
I need to mock this validator.
- 1,608
3
votes
1
answer
2k
views
Run attribute validator only after __attrs_post_init__ ends
I have:
@attr.s
class Example:
number = attr.ib(validator=attr.validators.instance_of(int), init=False)
def __attrs_post_init__(self):
self.number = 'string'
print('It seems, ...
- 1,608
4
votes
1
answer
475
views
What is the difference between super() and explicit super(Cl,self) (with __slots__ and attrs)
I'm using the attrs python package, in combination with inheritance and slots. I want to call the parent class's method from within the derived method. The problem is demonstrated below:
import attr
...
- 910
17
votes
3
answers
9k
views
How to achieve the reverse of "attr.asdict(MyObject)" using Python module 'attrs'
In documentation of Python module attrs stated that there is a method to convert attributes’ class into dictionary representation:
Example:
>>> @attr.s
... class Coordinates(object):
... ...
- 2,971
23
votes
1
answer
9k
views
When and why should I use attr.Factory?
When and why should I use attr.ib(default=attr.Factory(list)) over attr.ib(default=[])?
From the docs I see that a Factory is used to generate a new value, which makes sense if you are using a lambda ...
- 615
15
votes
2
answers
6k
views
Perfect forwarding - in Python
I am a maintainer of a Python project that makes heavy use of inheritance. There's an anti-pattern that has caused us a couple of issues and makes reading difficult, and I am looking for a good way ...
- 2,761
3
votes
5
answers
1k
views
How To Deduce Or Subtype Named Tuple From Another Named Tuple?
Preface
I was wondering how to conceptualize data classes in a pythonic way.
Specifically I’m talking about DTO (Data Transfer Object.)
I found a good answer in @jeff-oneill question “Using Python ...
- 2,971
0
votes
2
answers
612
views
Python attrs library and referencing instance methods
How can I convert the class below to use the attrs library:
class MyClass(object):
def __init__(self, api, template=None, **kwargs):
self.api = api
self.param1 = param1
if ...
- 26
3
votes
8
answers
929
views
Use Python for Creating JSON
I want to use Python for creating JSON.
Since I found no library which can help me, I want to know if it's possible to inspect the order of the classes in a Python file?
Example
# example.py
class ...
- 27.8k
172
votes
10
answers
16k
views
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 this ...
- 12.1k