# 12.2. Operators Numerical¶

## 12.2.1. Rationale¶

Operator

Method

obj + other

obj.__add__(other)

obj - other

obj.__sub__(other)

obj * other

obj.__mul__(other)

obj / other

obj.__truediv__(other)

obj // other

obj.__floordiv__(other)

obj ** other

obj.__pow__(other)

obj % other

obj.__mod__(other)

obj @ other

obj.__matmul__(other)

obj += other

obj.__iadd__(other)

obj -= other

obj.__isub__(other)

obj *= other

obj.__imul__(other)

obj /= other

obj.__idiv__(other)

obj //= other

obj.__itruediv__(other)

obj **= other

obj.__ipow__(other)

obj %= other

obj.__imod__(other)

obj @= other

obj.__imatmul__(other)

-obj

obj.__neg__()

+obj

obj.__pos__()

~obj

obj.__invert__()

## 12.2.2. Operator Module¶

>>> from operator import add
>>> from operator import sub
>>> from operator import mul
>>> from operator import truediv
>>> from operator import floordiv
>>> from operator import mod
>>> from operator import pow
>>> from operator import matmul
>>> from operator import neg
>>> from operator import pos
>>> from operator import invert


## 12.2.3. Example¶

>>> from dataclasses import dataclass
>>>
>>>
>>> @dataclass
... class Vector:
...     x: int
...     y: int
...
...         new_x = self.x + other.x
...         new_y = self.y + other.y
...         return Vector(new_x, new_y)
...
...         self.x += other.x
...         self.y += other.y
...         return self
...
>>>
>>>
>>> a = Vector(x=1, y=2)
>>> b = Vector(x=3, y=4)
>>> c = Vector(x=5, y=6)
>>>
>>> (a+b) + c
Vector(x=9, y=12)
>>>
>>> a += Vector(x=10, y=20)
>>> print(a)
Vector(x=11, y=22)


## 12.2.4. Use Case - Mod¶

• % (__mod__) operator behavior for int and str:

>>> 13 % 4
1
>>>
>>> '13' % '4'
Traceback (most recent call last):
TypeError: not all arguments converted during string formatting

>>> pi = 3.1514
>>>
>>>
>>> 'String: %s' % pi
'String: 3.1514'
>>>
>>> 'Double: %d' % pi
'Double: 3'
>>>
>>> 'Float: %f' % pi
'Float: 3.151400'

>>> firstname = 'Mark'
>>> lastname = 'Watney'
>>>
>>>
>>> 'Hello %s' % firstname
'Hello Mark'
>>>
>>> 'Hello %s %s' % (firstname, lastname)
'Hello Mark Watney'
>>>
>>> 'Hello %(fname)s %(lname)s' % {'fname': firstname, 'lname': lastname}
'Hello Mark Watney'

>>> class Str:
...     def __mod__(self, other):
...         """str substitute"""
...
...         if type(other) is str:
...             ...
...         if type(other) is tuple:
...             ...
...         if type(other) is dict:
...             ...


Note, that using %s, %d, %f is currently deprecated in favor of f'...' string formatting. More information in Builtin Printing

## 12.2.5. Assignments¶

"""
* Assignment: Operators Numerical Matmul
* Complexity: easy
* Lines of code: 3 lines
* Time: 3 min

English:
1. Overload @ operator
2. Set position based on argument tuple[int, int]
3. Run doctests - all must succeed

Polish:
1. Przeciąż operator @
2. Ustaw pozycję na podstawie argumentu tuple[int, int]
3. Uruchom doctesty - wszystkie muszą się powieść

Tests:
>>> import sys; sys.tracebacklimit = 0

>>> position = Position()
>>> position
Position(x=0, y=0)
>>> position @ (1, 2)
>>> position
Position(x=1, y=2)
"""

from dataclasses import dataclass

@dataclass
class Position:
x: int = 0
y: int = 0


"""
* Complexity: easy
* Lines of code: 3 lines
* Time: 5 min

English:
1. Override operator += for code to work correctly
2. Run doctests - all must succeed

Polish:
1. Nadpisz operatory += aby poniższy kod zadziałał poprawnie
2. Uruchom doctesty - wszystkie muszą się powieść

Hints:
* obj.__iadd__(other) -> self

Tests:
>>> import sys; sys.tracebacklimit = 0

>>> astro = Astronaut(firstname='Jan', lastname='Twardowski', missions=[
...     Mission(1969, 'Apollo 11'),
... ])
>>> astro += Mission(2024, 'Artemis 3')
>>> astro += Mission(2035, 'Ares 3')

>>> print(astro)  # doctest: +NORMALIZE_WHITESPACE
Astronaut(firstname='Jan', lastname='Twardowski',
missions=[Mission(year=1969, name='Apollo 11'),
Mission(year=2024, name='Artemis 3'),
Mission(year=2035, name='Ares 3')])
"""

from dataclasses import dataclass

@dataclass
class Astronaut:
firstname: str
lastname: str
missions: list

@dataclass
class Mission:
year: int
name: str