1. Object oriented programming¶

1.1. Class creation¶

class Human:
    pass

adam = Human()

1.2. Constructor¶

is explaining what values should be assigned during creation of an instance

class Human:
    def __init__(self, name):
        self.name = name

eve = Human('Eve')
print(eve.name)

Eve

1.3. Self¶

self is like this in other languages like java/c#,
Its pointing to our instance/object,
It could be named different but self is convention

1.4. Instance vs class¶

class Human is a class (just concept / definition),
adam = Human('Adam') is creation of an object/instance,
adam is an object (concrete - creation of concept)

class Human:

    def __init__(self, name):
        self.name = name

adam = Human('Adam')
print(adam.name)

Adam

1.5. Class variables¶

variables which stay the same across different objects

class Human:
    species = 'homo-sapiens'

    def __init__(self, name):
        self.name = name

print(Human.species)
adam = Human('Adam')
print(adam.name)
print(adam.species)

homo-sapiens
Adam
homo-sapiens

1.6. Special methods¶

Method	Parameters	Operator	Meaning
add	(self, other)	+	Adding objects
sub	(self, other)		Subtracting objects
len	(self)	len	Getting length of an object
contains	(self, other)	in	Check if in
str	(self)	str	Convert object to str
repr	(self)	repr	Get representation of object

1.7. Composition¶

1.8. Aggregation¶

1.9. Composition vs Aggregation¶

Composition	Composition	Aggregation
Creation	Inside	Outside
Deletion	With main ob	Independent

1.10. Example¶

import random

class Car:
    colors = ['red', 'blue', 'black']

    def __init__(self, brand='', color=None):
        self.brand = brand

        if not color:
            self.color = random.choice(self.colors)

    def __repr__(self):
        return "<{class_name} of brand: {brand} and color: {color}>".format(
            class_name=self.__class__.__name__,
            brand=self.brand,
            color=self.color
        )

    def __str__(self):
        return "{color} {brand} car".format(color=self.color, brand=self.brand)

bmw = Car('Bmw')
repr(bmw)
str(bmw)

1.11. Checking types¶

Note

check this code here

1.12. Exercises - part 1¶

Create class mechanical_vehicle, which is inheriting after vehicles,
When we create mechanical vehicle we need to know its unique id - its called VIN number,
Add fields:

Fuel consumption per 100 km

Add properties (property decorator) - miles left

Add method go(how_far) - this should change fuel_amount state and milage state,

1.13. Exercises - part 2¶

Create class Server which got:

Name,

Ip,

Create ping method (use os – execute ping command),

Change representation and conversion to string methods,

Store history of ping - date and status,

Create list of hosts for pinging [ ‘127.0.0.1’, …..],

Iterate over the list and print message for hosts if they are pingable

Hint

Use os library

Hint

Library __pathlib__ (std). Class PurePath:

Hint

Library ldap3:

1.14. Exercises - part 2¶

Create class Cluster which got:

Location,

Name

Its also to do len and add + on Cluster object