skip to navigation
skip to content

cylitestblarghblargh 15.3.0

Attributes without boilerplate.

attrs is an MIT-licensed Python package with class decorators that ease the chores of implementing the most common attribute-related object protocols:

>>> import attr
>>> @attr.s
... class C(object):
...     x = attr.ib(default=42)
...     y = attr.ib(default=attr.Factory(list))
>>> i = C(x=1, y=2)
>>> i
C(x=1, y=2)
>>> i == C(1, 2)
>>> i != C(2, 1)
>>> attr.asdict(i)
{'y': 2, 'x': 1}
>>> C()
C(x=42, y=[])
>>> C2 = attr.make_class("C2", ["a", "b"])
>>> C2("foo", "bar")
C2(a='foo', b='bar')

(If you don’t like the playful attr.s and attr.ib, you can also use their no-nonsense aliases attr.attributes and attr.attr).

You just specify the attributes to work with and attrs gives you:

  • a nice human-readable __repr__,
  • a complete set of comparison methods,
  • an initializer,
  • and much more

without writing dull boilerplate code again and again.

This gives you the power to use actual classes with actual types in your code instead of confusing tuples or confusingly behaving namedtuples.

So put down that type-less data structures and welcome some class into your life!


I wrote an explanation on why I forked my own characteristic. It’s not dead but attrs will have more new features.

attrs’s documentation lives at Read the Docs, the code on GitHub. It’s rigorously tested on Python 2.6, 2.7, 3.3+, and PyPy.


attrs is written and maintained by Hynek Schlawack.

The development is kindly supported by Variomedia AG.

It’s the spiritual successor of characteristic and aspires to fix some of it clunkiness and unfortunate decisions. Both were inspired by Twisted’s FancyEqMixin but both are implemented using class decorators because sub-classing is bad for you, m’kay?

The following folks helped forming attrs into what it is now:

Of course characteristic’s hall of fame applies as well since they share a lot of code.

File Type Py Version Uploaded on Size
cylitestblarghblargh-15.3.0.tar.gz (md5) Source 2016-05-25 33KB