Python Advanced Cheat Sheet by Rajargs

Every real-world entity is an object.An object has Behaviour (things it does or performs) and Attributes (things that describe it).

For eg: A Chair object can have behaviour like Movement, Height Adjustment & Attributes like Color, Make & Model, and Price.

It means wrapping data into a single unit & securing it.

For eg: Drug Capsule wraps different medicines into a single unit and protects them from the outside enviro­nment.
Bank Locker wraps your valuables into a single unit(l­ocker) and protects it via passcode.

Abstract class is a class that cannot be instan­tiated. However, you can create classes that inherit from an abstract class. An abstract method is an method without an implem­ent­ation. An abstract class may or may not include abstract methods.

Python doesn’t directly support abstract classes. But it does offer a module that allows you to define abstract classes.To define an abstract class, you use the abc (abstract base class) module.

Ex:
from abc import ABC, abstra­ctm­ethod
class Polygo­n(ABC):
@abstr­act­method
def noofsi­des­(self):
pass

The collection of all related objects is called a class.C­on­sider class as a general category which contains all the related objects inside it.

For eg: Objects like Wheelc­hair, Office Chair and Wooden Chair can be a part of the "­Cha­ir" class.

Hiding complexity from the user and showing only the relative stuff.

For Eg: In Car, all the complexity like the engine, machinery, etc is hidden from you; only relevant parts are shown, like the brakes, accele­rator, and gearbox.

Generators are functions that return an iterable generator object. Because the values from the generator object are fetched one at a time rather than the entire list at once, you can use a for-loop, next(), or list() function to get the actual values. Generator functions act just like regular functions with just one difference that they use the Python yield keyword instead of return .

Code:

def test_s­equ­ence():
num = 0
while num<10:
yield num
num += 1
for i in test_s­equ­ence():
print(i, end=",")

Output: 0,1,2,­3,4­,5,­6,7,8,9

The way we inherited a few qualities from our parents similarly, a class can also inherit the qualities from a parent class.

For eg: A Phone Class can have two Child Classes: 1) TelePhone
and 2) Mobile­Phone. Both can inherit the "­cal­lin­g" behaviour.

Different types of Inheri­tance:
 ­ ­ ­ Single inheri­tance: When a child class inherits from only one parent class, it is called single inheri­tance. We saw an example above.
 ­ ­ ­ Multiple inheri­tances: When a child class inherits from multiple parent classes, it is called multiple inheri­tances.
 ­ ­ ­ Multilevel inheri­tance: When we have a child and grandchild relati­onship.
 ­ ­ ­ Hierar­chical inheri­tance: More than one derived class are created from a single base.
 ­ ­ ­ Hybrid inheri­tance: This form combines more than one form of inheri­tance. Basically, it is a blend of more than one type of inheri­tance.

It means many forms. With the same name, it provides different forms.

For eg: In Chess, we've 6 pieces - king, rook, bishop, queen, knight, and pawn. All of them "­mov­e" differ­ently i.e. Bishop moves diagon­ally, Rooks move horizo­ntally and vertic­ally, etc.