dir()

dir([object])

Returns: list · Added in v3.0 · Updated March 13, 2026 · Built-in Functions

introspection built-in debugging exploration

The dir() function is one of Python’s most useful introspection tools. It returns a list of all valid attributes and methods available on an object or in the current scope. When called without arguments, it returns names in the current local scope. When called with an object, it returns that object’s attributes.

Syntax

dir()
dir(object)

Parameters

Parameter	Type	Default	Description
`object`	`any`	`None`	Optional. Any Python object. If omitted, returns names in the current local scope.

Returns: A list of strings representing attribute names.

Examples

Basic usage — current scope

# dir() without arguments returns names in current scope
print(dir())
# [__builtins__, __doc__, __loader__, __name__, __package__]

Exploring an object’s attributes

# dir() on a string object
my_string = "hello"
attrs = dir(my_string)
print(len(attrs))  # 47 attributes on a string
# 47

# Filter to just public methods
public_methods = [a for a in dir(my_string) if not a.startswith(_)]
print(public_methods)
# [capitalize, casefold, center, count, encode, endswith, 
#  expandtabs, find, format, format_map, index, isalnum, 
#  isalpha, isascii, isdecimal, isdigit, isidentifier, 
#  islower, isnumeric, isprintable, isspace, istitle, 
#  isupper, join, ljust, lower, lstrip, maketrans, 
#  partition, removeprefix, removesuffix, replace, rfind, 
#  rindex, rjust, rpartition, rsplit, rstrip, split, 
#  splitlines, startswith, strip, swapcase, title, 
#  translate, upper, zfill]

Exploring a custom class

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    
    def greet(self):
        return f"Hello, I'm {self.name}"

# See all attributes of a Person instance
p = Person("Alice", 30)
attrs = dir(p)

# Check if an attribute exists
print(name in attrs)
# True
print(greet in attrs)
# True
print(email in attrs)  # Not set
# False

Dynamic attribute access

class Calculator:
    def add(self, a, b):
        return a + b
    
    def multiply(self, a, b):
        return a * b

calc = Calculator()

# Find all callable methods dynamically
callable_attrs = [attr for attr in dir(calc) 
                  if callable(getattr(calc, attr)) and not attr.startswith(_)]
print(callable_attrs)
# [add, multiply]

Common Patterns

Interactive exploration in REPL

# Use dir() to explore unknown modules
import json
print(dir(json))
# [JSONDecodeError, JSONDecoder, JSONEncoder, __all__, __author__, 
#  __builtins__, __cached__, __doc__, __file__, __loader__, 
#  __name__, __package__, __spec__, dump, dumps, load, loads]

# Explore what you can do with the module
functions = [name for name in dir(json) if not name.startswith(_)]
print(functions)
# [JSONDecodeError, JSONDecoder, JSONEncoder, dump, dumps, load, loads]

Docstring discovery

# Get docstrings for methods
my_list = [1, 2, 3]
print(my_list.append.__doc__)
# Append object to the end of the list.

print(my_list.sort.__doc__)
# Sort the list in ascending order and return None.

Errors

TypeError: Raised when dir() is called with more than one argument.

dir(1, 2)
# TypeError: dir expected at most 1 argument, got 2