Python Operator Overloading

1) __str__ Overload

Create a Person class with name and age, override __str__ so printing the object shows:

name – age

---

2) __add__ for Numbers

Define a class NumberObj holding an integer. Implement __add__ so:

NumberObj(3) + NumberObj(4) → NumberObj(7)

---

3) __eq__ Comparison

Create a class Point with x and y. Overload __eq__ so two points are equal if both coordinates match.

---

4) __lt__ / <

Extend Point so:

Point(1,2) < Point(3,4)

compares based on sum of coordinates.

---

5) __len__ Overload

Define a class MyList storing a list internally. Overload __len__ to return its length.

---

6) __getitem__

In MyList, support indexing:

mylist[0]

returns first element.

---

7) __setitem__

In MyList, allow assigning:

mylist[1] = 10

---

8) __contains__ for in

Overload so:

x in myobj

works, based on internal list.

---

9) __sub__ Overload

Implement subtraction for NumberObj:

n1 – n2

---

10) __mul__ for Scaling

Create class Vector2D(x,y) and overload * to scale:

Vector2D(2,3) * 2 → Vector2D(4,6)

---

11) __add__ for Strings

Define a class wrapping a string so + joins text.

---

12) Polymorphic __add__

Make __add__ work when adding object + raw number (not object).

---

13) __repr__ Overload

Add __repr__ to a class so that when the object is printed in a list, it looks readable.

---

14) __neg__ for Unary -

In class NumberObj, overload unary minus to flip sign.

---

15) __gt__ / >

Compare two durations (e.g., hours attribute) using >.

---

16) Overload ==/!= Together

Create a class representing a book; consider two books equal if title and author match.

---

17) Custom Addition for Composite

Define class Student with grades list; overload + to merge grade lists.

---

18) __add__ & __iadd__

Implement both __add__ and __iadd__ so:

obj += obj2

updates internal contents.

---

19) Overload Comparison Chain

Implement both < and <= consistently for a class wrapping an integer.

---

20) __mul__ for Repeated Objects

In a custom string wrapper class, overload * so:

mystr * 3

repeats the text.

---

🧠 Concepts Practiced

Operator	Special Method
Addition	__add__
Subtraction	__sub__
Multiplication	__mul__
Length	__len__
Equality	__eq__
Greater / Less	__gt__, __lt__
Index access	__getitem__, __setitem__
Contains (in)	__contains__
String rep	__str__, __repr__
Unary negation	__neg__

---

📌 Example Starter

Assignment 2: __add__ for Numbers

class NumberObj:
    def __init__(self, value):
        self.value = value

    def __add__(self, other):
        return NumberObj(self.value + other.value)

    def __str__(self):
        return str(self.value)

a = NumberObj(3)
b = NumberObj(4)
c = a + b
print(c)  # 7

---

canvil: 333f6c7d-6876-4f7e-b6ad-1bdb2233f5c1