The dir() function is a built-in Python function used to list all attributes and methods available in an object, module, or class. It helps developers explore and debug Python objects.

---

🔹 Syntax

dir(object)  # Returns a list of attributes and methods of the object

• If no object is passed, dir() returns the list of all available names in the current scope.
• If an object (module, class, function, etc.) is passed, it returns the list of available attributes and methods for that object.

---

🔹 Example 1: Using dir() Without Arguments

print(dir())  # Lists all available names in the current scope

🔹 Output (Example)

['__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__']

---

🔹 Example 2: Using dir() With a Module

import math
print(dir(math))  # Lists all functions and attributes in the math module

🔹 Output (Truncated)

['__doc__', '__loader__', '__name__', '__package__', '__spec__', 'acos', 'asin', 'atan', 'ceil', 'cos', 'exp', 'factorial', 'floor', 'log', 'pi', 'sqrt']

🎯 This helps find available functions like sqrt(), log(), and pi.

---

🔹 Example 3: Using dir() With an Object

class Sample:
    def method1(self):
        pass
    def method2(self):
        pass

obj = Sample()
print(dir(obj))  # Lists attributes and methods of the Sample class

🔹 Output (Truncated)

['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__le__', '__lt__', '__module__', '__ne__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'method1', 'method2']

🚀 The list includes special methods (__init__, __str__, etc.) and user-defined methods (method1(), method2()).

---

🔹 Example 4: Filtering Attributes

If you only want to see user-defined attributes, you can filter out built-in methods:

attributes = [attr for attr in dir(obj) if not attr.startswith('__')]
print(attributes)  # Output: ['method1', 'method2']

---

🔹 Example 5: Using dir() on Built-in Types

📌 dir() on a List

print(dir(list))

🔹 Output (Truncated)

['append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

🎯 This helps us find methods like .append(), .sort(), .pop(), etc.

---

🔹 Summary

Use Case	Example	Purpose
Get current scope	dir()	Lists all variables in the current environment
Inspect module	dir(math)	Lists all functions & attributes of math
Inspect object	dir(obj)	Lists all methods & attributes of obj
Inspect list	dir(list)	Shows available list methods
Filter attributes	[x for x in dir(obj) if not x.startswith('__')]	Shows only user-defined attributes

---

🎯 Key Takeaways

✅ dir() is useful for exploring Python objects.
✅ It helps discover available methods and attributes in a module or class.
✅ Filtering out __ methods gives user-defined attributes.

Do you need more real-world applications of dir()? 🚀