inspect.getmembers() vs __dict__.items() vs dir()

by

dir() allows you to customize what attributes your object reports, by defining __dir__().

From the manual, if __dir__() is not defined:

If the object is a module object, the list contains the names of the module’s attributes.

If the object is a type or class object, the list contains the names of its attributes, and recursively of the attributes of its bases.

Otherwise, the list contains the object’s attributes’ names, the names of its class’s attributes, and recursively of the attributes of its class’s base classes.

This is also what inspect.getmembers() returns, except it returns tuples of (name, attribute) instead of just the names.

object.__dict__ is a dictionary of the form {key: attribute, key2: atrribute2} etc.

object.__dict__.keys() has what the other two are lacking.

From the docs on inspect.getmembers():

getmembers() does not return metaclass attributes when the argument is a class (this behavior is inherited from the dir() function).

For int.__dict__.keys(), this is

['__setattr__', '__reduce_ex__', '__reduce__', '__class__', '__delattr__', '__subclasshook__', '__sizeof__', '__init__']

To summarize, dir() and inspect.getmembers() are basically the same, while __dict__ is the complete namespace including metaclass attributes.

More Related Contents:

  1. What does if __name__ == "__main__": do?
  2. What does __all__ mean in Python?
  3. Visibility of global variables in imported modules
  4. What exactly does “import *” import?
  5. How do I create a namespace package in Python?
  6. Python ElementTree module: How to ignore the namespace of XML files to locate matching element when using the method “find”, “findall”
  7. type object ‘datetime.datetime’ has no attribute ‘datetime’
  8. Remove namespace and prefix from xml in python using lxml
  9. Python: NameError: global name ‘foobar’ is not defined [duplicate]
  10. Django: “projects” vs “apps”
  11. Is it bad practice to use a built-in function name as an attribute or method identifier?
  12. Creating a class within a function and access a function defined in the containing function’s scope
  13. Namespaces with Module Imports
  14. What does “Symbol not found / Expected in: flat namespace” actually mean?
  15. What are Python namespaces all about
  16. What does if __name__ == “__main__”: do in Python?
  17. Python: Why should ‘from import *’ be prohibited?
  18. socket.error:[errno 99] cannot assign requested address and namespace in python
  19. How can a name be “unbound” in Python? What code can cause an `UnboundLocalError`?
  20. How to find “import name” of any package in Python?
  21. Python: Name resolution; order of function def’s
  22. Python modules with identical names (i.e., reusing standard module names in packages)
  23. How to modify the local namespace in python
  24. Python: deleting a class attribute in a subclass
  25. NameError: global name is not defined
  26. argparse subcommands with nested namespaces
  27. How do I parse and write XML using Python’s ElementTree without moving namespaces around?
  28. lxml: add namespace to input file
  29. What does ” ‘tuple’ object has no attribute ‘first_name’ mean in this situation?
  30. How do you validate a URL with a regular expression in Python?

Leave a Comment