Python dir() function

dir() overview

The dir() function in Python returns a list of valid attributes of the given object. dir() can be used on data structures like lists, tuples, sets and dictionaries or user-defined objects like classes. This is useful to find attributes and methods of an object.

dir() on data structures

To return all valid attributes of a data structure use the dir() function. # check attributes of data structures myList = [1, 2, 3] print(dir(myList)) The dir() function returns a list of all attributes. ['__add__', '__class__', '__class_getitem__', '__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'] We can for example see that it's possible to call the following methods: .append() .clear() .copy() .extend() .count() .index() .insert() .pop() .remove() .reverse() .sort() on the list.

dir() on user-defined object

The dir() function is also useful to find the attributes of a user-defined object like a class. # using dir() to find attributes of a class class Person: age = 25 name = 'mike' mike = Person() print(dir(mike)) In this example mike has the attributes age and name. ['__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__', 'age', 'name']

dir() syntax

The syntax of dir() is: dir(object)

dir() arguments

The dir() function accepts only one object at a time. If more than one argument is passed, a TypeError exception is raised.

dir() return values

The dir() function returns a list of all valid attributes. If no object is passed, dir() returns a list of all variables in the current local scope. ['Person', '__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__', 'length', 'mike', 'my', 'myDictionary', 'myList', 'myString', 'myTuple']

related functions

Some related functions are: the hasattr() function to check if an object has an specific attribute the delattr() function to delete a specific attribute the getattr() function to receive the value of a specific attribute



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