How to document fields and properties in Python?

deamon picture deamon · May 19, 2011 · Viewed 20.1k times · Source

It's easy to document a class or method in Python:

class Something:
  """ Description of the class. """

  def do_it(self):
    """ Description of the method. """
    pass

  class_variable = 1 # How to comment?

  @property
  def give_me_some_special_dict(self):
    """ doesn't work! Doc of general dict will be shown. """
    return {}

But how to document a field or property for usage in API docs or help?

Answer

Eli Bendersky picture Eli Bendersky · May 19, 2011

Python has a PEP (257) that defines Docstring Conventions. Regarding documentation of attributes, it states:

String literals occurring immediately after a simple assignment at the top level of a module, class, or __init__ method are called "attribute docstrings".

So the following are considered documented attributes:

class Foo(object):
  velocity = 1  
  """Foo's initial velocity - class variable"""

  def __init__(self, args):
    self.location = 0.0 
    """Foo's initial location - instance variable"""   

(Edit: Fixed second docstring)