RR Education

बच्चों का भविष्य होगा " रौशन "

Python Programming

What is Programming?

Just like we use Hindi or English to communicate with each other, we use a Programming language to communicate with the computer.

Programming is a way to instruct the computer to perform various tasks.

What is Python?

Python is a simple and easy-to-understand language that feels like reading simple English. This Pseudo code nature of Python makes it easy to learn and understandable for beginners.

Features of Python:

• Easy to understand = Less development time
• Free and open source
• High-level language
• Portable – works on Windows/Linux/Mac
• + Fun to work with :)

Installation

Python can be easily installed from python.org

When you click on the download button, python can be installed right after you complete the setup by executing the file for your platform.

Tip: Just install it like a game ☻

Chapter 1: Modules, Comments & Pip

Let’s write our very first python program.

Create a file called hello.py and paste the below code into it

Execute this file (.py file) by typing python hello.py, and you will see Hello World printed on the screen.

Modules

A module is a file containing code written by somebody else (usually) which can be imported and used in our programs.

Pip

Pip is a package manager for python. You can use pip to install a module on your system.

E.g., pip install flask (It will install flask module in your system)

Types of modules

There are two types of modules in Python:

1. Built-in modules – Pre-installed in Python
2. External modules – Need to install using pip

Some examples of built-in modules are os, abc, etc.

Some examples of external modules are TensorFlow, flask, etc.

Using Python as a Calculator

We can use python as a calculator by typing “python” + TO DO on the terminal. [It opens REPL or read evaluation print loop]

Comments

Comments are used to write something which the programmer does not want to execute.

Comments can be used to mark the author's name, date, etc.

Types of Comments:

There are two types of comments in python,

1. Single line comments – Written using # (pound/hash symbol)
2. Multi-line comments – Written using ’’’ Comment ’’’ or ’”” Comment ’””.

Chapter 1 – Practice Set

1. Write a program to print Twinkle-Twinkle Little Star poem in python.
2. Use REPL and print the table of 5 using it.
3. Install an external module and use it to perform an operation of your interest.
4. Write a python program to print the contents of a directory using os module. Search online for the function which does that.
5. Label the program written in problem 4 with comments.

Chapter 2 – Variables and Data Types

A variable is a name given to a memory location in a program. For example

Variable – Container to store a value

Keywords – Reserved words in Python

Identifiers – class/function/variable name

Data Types:

Primarily there are the following data types in Python:

1. Integers
2. Floating point numbers
3. Strings
4. Booleans
5. None

Python is a fantastic language that automatically identifies the type of data for us.

a = 31
  
  type(a)                      #class<int>
  
  b = “31”
  
  type(b)                      #class<str>

Str(31)           # ”31” Integer to string conversion
  
  int(“32”)       # 32 String to int conversion
  
  float(32)       #32.0 Integer to float conversion

a = input(“Enter name”)               #if a is “Raushan”, the user entered Raushan

word = “amazing”
  
  word[1:6:2]           # It will return ’mzn’

word = ‘amazing’
  
  word[:7] or word[0:7]      #It will return ‘amazing’
  
  word[0:] or word[0:7]      #It will return ‘amazing’

len(‘Raushan’)               #Returns 7

letter = ‘’’ Dear <|NAME|>,
  
                          You are selected!
  
                          <|DATE|>

letter = “Dear Raushan, This Python course in nice. Thanks!!”

friends = [‘Apple’, ‘Akash’, ‘Rohan’, 7, False]

L1 = [7, 9, ‘Raushan’]
  
  L1[0] – 7
  
  L1[1] – 9
  
  L1[70] – Error
  
  L1[0:2] – [7,9]         (This is known as List Slicing)

L1 = [1, 8, 7, 2, 21, 15]

a = ()              #It is an example of empty tuple
  
  a = (1,)           #Tuple with only one element needs a comma
  
  a = (1, 7, 2)   #Tuple with more than one element

a = (1, 7, 2)

a = (7, 0, 8, 0, 0, 9)

''' a = {“key”: “value”,
  “Raushan”: “code”,
  “marks” : “100”,
  “list”: [1,2,9]}
  a[“key”]	# Prints value
  a[“list”] 	# Prints [1,2,9] '''
  

a = {“name”: “Raushan”,
      “from”: “India”,
      “marks”: [92,98,96]}

S= Set()          # No repetition allowed!
  
  S.add(1)
  
  S.add(2)
  
  # or Set = {1,2}

S = {1,8,2,3}

S = Set()
  
  S.add(20)
  
  S.add(20.0)
  
  S.add(“20”)

S = {8, 7, 12, “Raushan”, [1, 2]}

'''
  if (condition1):		// if condition 1 is true
      print(“yes”)
  elif (condition2):		// if condition 2 is true
      print(“No”)
  else:				// otherwise
      print(“May be”)
  '''
  

a = 22
  if (a>9):
      print(“Greater”)
  else:
      print(“lesser”)

= = -> equals
  
  >=  -> greater than/equal to
  
  <=, etc.

and -> true if both operands are true else false
  
  or -> true if at least one operand is true else false
  
  not -> inverts true to false and false to true

'''
  if (condition1):
      #code
  elif (condition 2):
      #code
  elif (condition 2):
      #code
  ….
  else:
      #code    '''