71 - dir, dict and help methods

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2024-02-23 - 16:44

We must look into dir(), __dict__() and help() attribute/methods in python. They make it easy for us to understand how classes resolve various functions and executes code. In Python, there are three built-in functions that are commonly used to get information about objects: dir(), dict, and help(). Let's take a look at each of them:

The dir() method

dir(): The dir() function returns a list of all the attributes and methods (including dunder methods) available for an object. It is a useful tool for discovering what you can do with an object. Example:

>>> x = [1, 2, 3]
>>> dir(x)
>>> ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']   `

The __dict__ attribute

__dict__: The __dict__ attribute returns a dictionary representation of an object's attributes. It is a useful tool for introspection. Example:

>>> class Person:
...     def __init__(self, name, age):
...         self.name = name
...         self.age = age
...
>>> p = Person("John", 30)
>>> >>> p.__dict__

Output

{'name': 'John', 'age': 30}

The help() mehthod

help(): The help() function is used to get help documentation for an object, including a description of its attributes and methods. Example:

>>> help(str)
Help on class str in module builtins:

class str(object
	|  str(object='') -> str
	|  str(bytes_or_buffer[, encoding[, errors]]) -> str
	|
	|  Create a new string object from the given object. If encoding or 
	|  errors is specified, then the object must expose a data buffer
	|  that will be decoded using the given encoding and error handler.
	|  Otherwise, returns the result of object.__str__() (if defined)
	|  or repr(object).
	|  encoding defaults to sys.getdefaultencoding().
	|  errors defaults to 'strict'.

In conclusion, dir(), dict, and help() are useful built-in functions in Python that can be used to get information about objects. They are valuable tools for introspection and discovery.

Main Example

class Person:
  def __init__(self, name, age):
      self.name = name
      self.age = age
      self.version = 1

    
p = Person("John", 30)
print(p.__dict__)

print(help(Person))