Python dir() function With Examples [Latest]

Python dir()

Python dir() function syntax is:

dir([object])

If the object contains __dir__() function, then this function will be called. This function must return the list of attributes.

The list of attribute names is sorted in alphabetical order.

Let’s look at some examples of dir() function.

dir() with no argument

print('ndir() with no argumentn')
print(dir())

Output:

dir() with no argument
['__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__']

Note that the output depends on the program and python installation, so don’t worry if it’s different in your system.

dir() with tuple and list

print('ndir() with tuple argumentn')
t = (1, 2)
print(dir(t))
print('ndir() with list argumentn')
l = [1, 2]
print(dir(l))

Output:

dir() with tuple argument
['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'count', 'index']
dir() with list argument
['__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']

Note that the elements in the list are sorted alphabetically.

dir() with custom object

class Data:
    id = 0
    name=""
print('ndir() with custom object argumentn')
d = Data()
print(dir(d))

Output:

dir() with custom object argument
['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'id', 'name']

dir() with module object

Let’s see the output of dir() function with a module object, I am using namedtuple from collections module.

from collections import namedtuple
n = namedtuple('Vowels', 'a,e,i,o,u')
print('ndir() with module object argumentn')
print(dir(n))

Output:

dir() with module object argument
['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__module__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmul__', '__setattr__', '__sizeof__', '__slots__', '__str__', '__subclasshook__', '_asdict', '_fields', '_fields_defaults', '_make', '_replace', 'a', 'count', 'e', 'i', 'index', 'o', 'u']

Note that the module’s attributes are also returned by dir() function.

dir() with __dir__() function

Let’s define a class with __dir__() function and see if it’s called by dir() function or not.

class Color:
    def __dir__(self):
        print('__dir__() function called')
        return ['Red', 'Green', 'Blue']
print('ndir() with __dir__ method defined in objectn')
c = Color()
print(dir(c))

Output:

dir() with __dir__ method defined in object
__dir__() function called
['Blue', 'Green', 'Red']

Summary

Python dir() is a convinience function to determine the available attributes of an object or the attributes of local scope.

Reference: Official Documentation