Free Python Course: Basics For Novices In Hindi In 42 Mins

This video explains how to install the correct version of python

=============================== Notes =====================================

Download link:        https://www.python.org/downloads/release/python-3810/

Depending upon your OS type, select the correct version

This videos explains rules for naming variables in python

=============================== Notes =====================================

rules for naming variables:

1. must start from an alphabet or undercore "_" only first, place_delhi, _location are valid names

2. can't start with a digit

Eg. 9times, 21century are invalid names

3. can have digits in between

Eg. number2, number_2, number_2_times are valid names

4. can't have any character other than underscore "_"

Eg. price$20 is an invalid name

This video gives the introduction to Google Colab

=============================== Notes =====================================

Google colab link: https://colab.research.google.com/

This video explains the different ways to use print function in python

=============================== Notes =====================================

use of print function: to give the output on screen

There are 5 ways to use print function:

1. standard way

2. tuple format

3. string concatenation

4. format function

5. f-strings

This video explains the standard way to print in python

=============================== Notes =====================================

use of print function: to give the output on screen

There are 5 ways to use print function:

1. standard way

2. tuple format

3. string concatenation

4. format function

5. f-strings

1. standard way:

a = 10

print("value of a = ",a)

This video explains the use of comments in python

=============================== Notes =====================================

Use of comments in python:  sometimes we want to prevent the execution of a piece of code (may be for documentation purpose), we can use comments and can place that piece of code inside comments.

comments are of 2 types:

a) single line comments

eg.

print("hello")

# this is a single line comment

print("world")

b) multi-line comments

eg.

print("hello")

''' this is a multi line comment

this will not be executed '''

print("world")

note: single line comment can also be used as multi line comment

eg.

print("hello")

# this is a single line comment

# acting as a multi line comment

# this will not be executed

print("world")

This video explains the tuple format to print in python

=============================== Notes =====================================

use of print function: to give the output on screen

There are 5 ways to use print function:

1. standard way

2. tuple format

3. string concatenation

4. format function

5. f-strings

2. tuple format: (we need to use format specifiers)

for integers, use %d

for strings, use %s

for float, use %f

a = 10

print("value of a = %d" % a)

a = 10

b = 20

print("value of a = %d and b = %d" % (a,b))

This video explains the concept of concatenation in python

=============================== Notes =====================================

concept of concatenation in python:

age = 28

name = "sumit"

salary = 1000

print(salary + age)

print("my username is",name + age)

# print("my username is",name + str(age))

This video explains the string concatenation way to print in python

=============================== Notes =====================================

use of print function: to give the output on screen

There are 5 ways to use print function:

1. standard way

2. tuple format

3. string concatenation

4. format function

5. f-strings

3. string concatenation

a = 10

b = 20

print("value of a = " + str(a) + " and b = " + str(b))

# print("value of a = ",a," and b = ",b)                                  # standard way

This video explains the format function to print in python

=============================== Notes =====================================

use of print function: to give the output on screen

There are 5 ways to use print function:

1. standard way

2. tuple format

3. string concatenation

4. format function

5. f-strings

4. format function

a = 10

b = 20

print("value of a = {} and b = {}".format(a,b))

# print("value of a = {0} and b = {1}".format(a,b))

# print("value of a = {1} and b = {0}".format(a,b))

This video explains the f-strings to print in python

=============================== Notes =====================================

use of print function: to give the output on screen

There are 5 ways to use print function:

1. standard way

2. tuple format

3. string concatenation

4. format function

5. f-strings

5. f-strings (formatted strings)

a = 10

b = 20

print(f"value of a = {a} and b = {b}")

This video explains the input function in python

=============================== Notes =====================================

input() function is used to read values from the screen. It reads the value in string format

number = input()

print(number)

# to read a value with some custom message

number = input("Enter the number: ")

print(number)

This video explains the operators in python

=============================== Notes =====================================

Operators in python:

▪ Logical ( and, or, not )

▪ Arithmetic ( +, -, *, /, //, %, ** )

▪ Relational ( ==, !=, etc. )

▪ Assignment ( = ) and Shorthand ( +=, -=, *=, /=, //=, %=, **= )

▪ Membership ( in, not in )

▪ Identity ( is, is not )

▪ Shift

▪ Bitwise ( &, |, ^ )

This video explains the use of sep parameter in print function in python

=============================== Notes =====================================

use of "sep" parameter in print function in python:

values will be separated with this value

its default value is a whitespace (" ")

print("it","is","raining","today")

Output: it is raining today

print("it","is","raining","today",sep="#")

Output: it#is#raining#today

This video explains the use of end parameter in print function in python

=============================== Notes =====================================

use of "end" parameter in print function in python:

its default value is newline ("\n")

print("my name is khan")

print("I live in Dwarka ")

print("my name is khan",end="")

print("I live in Dwarka ")

This video explains the use of import in python

=============================== Notes =====================================

use of import in python:

print("importing complete file...\n")

import a_and_b

print("a_and_b.a = ",a_and_b.a)

print("a_and_b.b = ",a_and_b.b)

print()

print()

print("importing only the variables...\n")

from a_and_b import a,b

print("a = ",a)

print("b = ",b)

This video explains the use of if statement in python

=============================== Notes =====================================

"if" statement can be used for selection in case we need to check for a condition:

print("you are a nice person")

a = input("Is Delhi capital of India: ")

if a == "Y":

    print("you are smart too")

print("thanks")

This video explains the use of if-else statement in python

=============================== Notes =====================================

"if-else" statement can be used for selection in case we have two possible cases:

print("you are a nice person")

a = input("Is Delhi capital of India: ")

if a == "Y":

    print("you are smart too")

else:

    print("you are not that smart")

print("thanks")

This video explains the use of if-elif-else statement in python

=============================== Notes =====================================

"if-elif-else" statement can be used for selection in case we have multiple possible cases:

choice = input("select your desired t-shirt colour (r/g/b): ")

if choice == "r":

    print("you picked red colour")

elif choice == "g":

    print("you picked green colour")

elif choice == "b":

    print("you picked blue colour")

else:

    print("incorrect choice")

This video explains the range function in python

=============================== Notes =====================================

range function in python:

It returns a collection of values

range(start, end, step)

start and step are optional while end parameter is mandatory

default value of "start" is 0 and "step" is 1

range(5)   # (0,1,2,3,4)

range(2,5)   # (2,3,4)

range(2,10,2)   # (2,4,6,8)

range(10,5,-1)   # (10,9,8,7,6)

This video explains the for loop in python

=============================== Notes =====================================

for loop can be used to iterate over a collection:

value from the collection will be received by the loop variable one by one

range(5) will return (0,1,2,3,4)

for i in range(5):

    print(i)

Output:

0

1

2

3

4

This video explains the while loop in python

=============================== Notes ===================================== while loop can be used if we want to perform iteration using a specific condition

3 aspects of while loop:

initialization of loop variable

condition check

updation of loop variable

i = 1                      # initialization

while i <= 10:     # condition check

    print(i)

    i = i + 1            # updation

Output:

1

2

3

4

5

6

7

8

9

10

This video explains the strings in python

=============================== Notes =====================================

strings are immutable collections whose value once assigned can't be modified later

name = "Sumit"

or

name = 'Sumit'

strings support indexing (starting from 0)

print(name[0])     # "S"

name[0] = "P"     # error

strings also support slicing

name = "Washington"

print(name[2:6])     # "shin"

This video explains the lists in python

=============================== Notes =====================================

list is a mutable collection (its contents can be changed) which can store any type of values

list can be created either by using function or by square bracket [ ]

lst = list()

or

lst = [11, "Sumit", 1.5, True]

print(lst)

to add an element in list:

lst.append(22)

print(lst)

to remove an element from the last: l

st.pop()

print(lst)

to remove an element if index is known:

lst.pop(2)

print(lst)

This video explains the tuples in python

=============================== Notes =====================================

tuple is an immutable collection (its contents can't be changed directly) which can store any type of values

tuple can be created either by using function or by parenthesis bracket ()

tup = tuple()

or

tup = (11, "Sumit", 1.5, True)

print(tup)

to change tuple values, first convert into list, do the changes and convert back to tuple:

print(tup)

tup = list(tup)

tup.append(22)

tup = tuple(tup)

print(tup)

This video explains the dictionaries in python

=============================== Notes =====================================

dict is a mutable collection (its contents can be changed) which stores the values as key-value pairs

dct = { "key1" : "value1", "key2" : "value2", "key3" : "value3" }

to add/update a pair:

dct["key4"] = "value4"

to remove a pair:

dct.pop("key4")

or

del dct["key4"]

This video explains the sets in python

=============================== Notes =====================================

set is a mutable collection (its contents can be changed) which can store any type of values but only unique values can be stored and duplicated values will be discarded

set can be created either by using function or by curly bracket {}

st = set()

or

st = {11, "Sumit", 1.5, True}

print(st)

to add an element in set:

st.add(22)

print(st)

to remove an element from the set:

st.remove(22)

print(st)

Note: sets don't support indexing

This video explains the exception handling in python

=============================== Notes =====================================

exception handling can be used to prevent our program to get crashed

try and except blocks are used

try:

the code which can throw the exception

except:

code to handle that exception

=== unhandled execution ===

first = int(input("enter first number: "))

second = int(input("enter second number: "))

print(first/second)

=== handled exception ===

try:

    first = int(input("enter first number: "))

    second = int(input("enter second number: "))

    print(first/second)

except:

    print("Division by zero is not allowed")

This video explains the functions in python

=============================== Notes =====================================

functions are a self executable piece of instructions which can be used for code reusability.

We can wrap the frequently used code inside a function body

non-parameterized functions:

def func():

    print("I am Sumit")

    print("I am in 12th standard")

    print("I am from XYZ school")

func()     # function call

parameterized functions:

def func(name,standard,school):

    print(f"I am {name}")

    print(f"I am in {standard}th standard")

    print(f"I am from {school} school")

func("Amit",11,"ABC")

function can return values as well using return keyword:

def multiplier(x,y):

    return x*y

result = multiplier(10,20)

print(result)

This video explains the OOPS concept in python

=============================== Notes =====================================

OOPS stands for Object Oriented Programming System

It works on the real world scenarios and in this system, data is given more importance rather than functions i.e. doing a task is more important instead of the way it is being done

It has 4 main priciples:

1. Data Encapsulation

2. Data Abstraction

3. Inheritance

4. Polymorphism

This video explains the classes and objects in python

=============================== Notes =====================================

Class:  It is a user defined data type which can be made with some features in it which its variables will be having. A class acts as a blue print.

Objects:  the running instance of a class is known as its object

Eg. A human being will have features like hands, legs, head, brain, heart. So, human being can be created as a class and its variables will have all these features

This video explains the static methods in python

=============================== Notes =====================================

static functions: which are just a part of a class and not related to any object of a class.

"@staticmethod" decorator needs to be used to declare a method as a static method

class Calc:

    @staticmethod

    def adder(a,b):

        print(a+b)

class name should be used to call a static method.

Calc.adder(10,20)

However, objects can also call it

obj = Calc()

obj.adder(30,40)

This video explains the class methods in python

=============================== Notes =====================================

class methods: they are used to manage the class data that can be shared by the whole class.

"@classmethod" decorator is used to declare a method as a class method.

class Employee:

    leaves = 12

    bonus = 10000

    @classmethod

    def get_leaves(cls):

        print(cls.leaves)

    @classmethod

    def get_bonus(cls):

        print(cls.bonus)

obj1 = Employee()

obj1.get_leaves()   # 12

obj1.get_bonus()   # 10000

obj2 = Employee()

obj2.get_leaves()   # 12

obj2.get_bonus()   # 10000

This video explains the instance methods in python

=============================== Notes =====================================

instance methods: different objects have different values of instance variables (data fields). Instance methods manage the data of instance variables.

class Calc:

    def __init__(self,n,a):

        self.name = n

        self.age = a

"init" method gets called automatically whenever an object gets created.

"self" is used to reference the invoking object

obj1 = Calc("Amit",20)

print(obj1.name," and ",obj1.age)

obj2 = Calc("Sumit",40)

print(obj2.name," and ",obj2.age)

This video explains the encapsulation in python

=============================== Notes =====================================

Data encapsulation: wrapping up of data fields and the related functions in a single unit is called as Data encapsulation.

A class is an example of data encapsulation

class HumanBeing:

    hands = 2

    legs = 2

    brain = 1

    heart = 1

person = HumanBeing()

print(person.hands)     # 2

This video explains the abstraction in python

=============================== Notes =====================================

Data Abstraction: showing only the useful data and hiding the irrelevant details is known as Data Abstraction

class HumanBeing:

    hands = 2

    legs = 2

    brain = 1

    heart = 1

person = HumanBeing()

print(person.hands)     # 2

This video explains the simple inheritance in python

=============================== Notes =====================================

Inheritance: transferring the features of one class into another class is known as Inheritance.

The class from which features are transferred is called Parent class and the class in which features are transferred is known as Child class

Types of inheritance:

1. simple

2. multiple

3. multilevel

4. hierarchical

5. hybrid

class Parent:

    cash = 100000

    cars = 2

    flats = 3

class Child(Parent):

    bike = 1

obj = Child()

print(obj.bike)   # 1

print(obj.cash)   # 100000

print(obj.cars)   # 2

print(obj.flats)   # 3

This video explains the multiple inheritance in python

=============================== Notes =====================================

Types of inheritance:

1. simple

2. multiple

3. multilevel

4. hierarchical

5. hybrid

multiple inheritance: whenever a class inherits from two or more parent classes

class Parent1:

    def func1(self):

        print("this is func1 from parent1")

class Parent2:

    def func2(self):

        print("this is func2 from parent2")

class Parent3:

    def func3(self):

        print("this is func3 from parent3")

class Child(Parent1, Parent2, Parent3):

    def func4(self):

        print("this is func4 from child")

obj = Child()

obj.func1()

obj.func2()

obj.func3()

obj.func4()

This video explains the multilevel inheritance in python

=============================== Notes =====================================

multilevel inheritance: inheritance happens at multiple levels

grandfather

    |

    |

father

    |

    |

child

class Grandfather:

    def grand_func(self):

        print("grand_func from grandfather")

class Father(Grandfather):

    def father_func(self):

        print("father_func from father")

class Child(Father):

    def func(self):

        print("func from child")

obj = Child()

obj.func()

obj.father_func()

obj.grand_func()

This video explains the hierarchical inheritance in python

=============================== Notes =====================================

Hierarchical inheritance: when there is a single parent class and multiple child classes

class Parent:

    def parent_func(self):

        print("this is parent_func from parent")

class Child1(Parent):

    def func1(self):

        print("this is func1 from child1")

class Child2(Parent):

    def func2(self):

        print("this is func2 from child2")

class Child3(Parent):

    def func3(self):

        print("this is func3 from child3")

obj1 = Child1()

obj2 = Child2()

obj3 = Child3()

obj1.parent_func()

obj2.parent_func()

obj3.parent_func()

This video explains the hybrid inheritance in python

=============================== Notes =====================================

Hybrid inheritance: when more than 1 type of inheritances are happening at the same time

                                 Parent

                                       |

                     ------------------------

                     |                                         |

                     |                                         |

                Child1                              Child2

                                                               |

                                                               |

                                                           Child3

This is an example of hierarchical as well as multilevel inheritances

class Parent:

    def parent_func(self):

        print("this is parent_func from parent")

class Child1(Parent):

    def func1(self):

        print("this is func1 from child1")

class Child2(Parent):

    def func2(self):

        print("this is func2 from child2")

class Child3(Child2):

    def func3(self):

        print("this is func3 from child3")

obj1 = Child3()

obj1.func2()

obj1.parent_func()

This video explains the method overloading in python

=============================== Notes =====================================

Polymorphism: Occurrence in multiple forms.

It is achieved by method overloading and operator overloading

Method overloading: calling a same method with different parameters at the same time

class Calc:

    @staticmethod

    def adder(a=0,b=0,c=0,d=0):

        print(a+b+c+d)

Calc.adder(10,20)

Calc.adder(10,20,30)

Calc.adder(10,20,30,40)

This video explains the operator overloading in python

=============================== Notes =====================================

Operator overloading: using a predefined operator with a user defined variable (object)

class Person:

    def __init__(self,a):

        self.age = a

    def __add__(self,obj):

        return self.age + obj.age

obj1 = Person(10)

obj2 = Person(20)

print(obj1 + obj2)

This video explains the comprehensions in python

=============================== Notes =====================================

Comprehensions: it is a shortcut to create a collection based on a certain condition

lst = []

for i in range(10):

    if i%2 == 0:

        lst.append(i)

print(lst)

print([i for i in range(10) if i%2 == 0])         # using comprehension

we can create a collection without any condition as well

print([i for i in range(10)])

comprehensions can also be used to create set and dict

This video explains the decorators in python

=============================== Notes =====================================

Decorator: it can be used to enhance the functionality of a function

def adder(a,b):

    print(a+b)

adder(10,20)

def dec(func):

    def inner(x,y):

        print("before function call")

        func(x,y)

        print("after function call")

    return inner

@dec                             # decorator applied

def adder(a,b):

    print(a+b)

adder(10,20)

Output:

before function call

30

after function call

This video explains the generators in python

=============================== Notes =====================================

Generators: we can generate the value only when the function is called instead of holding all the value in memory

gen = (i*i for i in range(10))

print(next(gen))

print(next(gen))

print(next(gen))

"yield" keyword can also be used to create a generator

def square(n):

    for i in range(n):

        yield i*i

gen2 = square(10)

print(next(gen2))

print(next(gen2))

print(next(gen2))

This video explains the lambda functions in python

=============================== Notes =====================================

Lambda functions: they are anonymous functions which can be used if a single line logic is there

def square(num):

    return num*num

print(square(20))       # 400

func = lambda x : x*x

print(func(10))            # 100

This video explains the monkey patching in python

=============================== Notes =====================================

Monkey patching: for testing purpose, we modify the functionality of a function and after testing, we can set it back to its original functionality

class Sample:

    def func1(self):

        print("this is func1 from Sample")

    def func2(self):

        print("this is func2 from Sample")

    def monkey_patch(self):

        print("this is a patch for testing")

patch = Sample.func2

Sample.func2 = Sample.monkey_patch           # monkey patching done

obj = Sample()

obj.func2()

Sample.func2 = patch                                      # functionality restored

obj.func2()

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