1. Modules, Comments & pip in Python

Let's write our very first python program. Create a file called hello.py and paste the below code in it:

print("Hello World")                                                                  ➡️ print is a function

Execute this file(.py file) by typing python hello.py on your terminal

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 the package manager for python you can use pip to install a module on your system 

➡️ pip install numpy installs numpy module

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, sys, abc, random etc.

Some examples of external modules are-

tensorflow, flask, Django, numpy etc.

Using Python as a Calculator

We can use python as a calculator by typing "python" + ↲ on the terminal.

➡️ This opens REPL or Road Evaluate Print loop

Comments

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

➡️ Can be used to mark author name , date etc.

Types of Comments

There are two types of comments in Python-

1. Single line comments     ➡️ Written using #

2. Multi line comments       ➡️ Written using ''' comment'''

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 in OS module documentation for the function which does that.

5. Label the program written in problem 4 with comments.

Answer of practice set

1.

3.

4.