Python Introduction

 

Python

 

Introduction

 

While learning something new, we normally have many questions like what , why, when and how , in our mind. So let's begin our Learning of Python Language with getting answers to them first before enjoying the Learning.

 

What is Python?

 

Python is a popular computer programming language. It was developed by Guido van Rossum, and released in 1991. Python is developed under an OSI-approved open source license, making it freely usable and distributable, even for commercial use. Python 1 was released in the year 1994. But major usages started only after year 2000 when python 2 was released. The last release of Python 2 was Python 2.7, released in the year 2010 and was stopped for further improvement only by 2020. The Language is still in evolving process mode only. The most recent major version is Python 3 (from DEC 2008 ), Current Version and release is 3.10, released as late as 2021 October and in 2022 October , 3.11 is expected for release and 2023 it is going to be 3.12.

 

One of the main reasons for the popularity of python would be its simplicity in syntax so that it could be easily read and understood even by amateur developer also.

 

What is it used for?

 

It is a Multipurpose language and can be used in development of variety of Applications, few popular Applications are

 

] Web Application development  (server-side)

] Networking Applications

] Application Software development

] Mathematics

] System Scripting

] Image Processing

 

Why is Python becoming Popular?

 

While the Language is still in evolving mode, we find Python being used in several major Applications and the main reasons behind that are

 

F It can work on different platforms (Windows ,Mac, Linux, Raspberry Pi,etc.)

F It has a simple syntax similar to the English language

F It has syntax that allows developers to write programs with fewer lines than some other programming languages.

F It runs on an interpreter system, meaning that code can be executed as soon as it is written. This means that prototyping can be very quick.

F It can be treated in a procedural way, an object-oriented way or a functional way.

 

 

How to use Python?

 

Basic requirement to RUN a python Program we require the Python Software to be installed in our system. Since the Software is open source License any one can download from our Web and Install in our system.

 

The software to be downloaded for Installation depends upon the Operating System being used and also the Architecture whether it is 32 bit or 62 bit one. In this book, we are going to follow the PYTHON 3.7 version, because it is Last Release that will work on Windows 7 Platform. (Since even now many are using Windows 7 , though officially it is discontinued by Microsoft, Let's take this as our Base) . If required you can Download Python 3.8 or 3.9 or 3.10 also.

 

On Installation of Python in our System, we can easily Develop Programs in Python and run them.

 

There are several ways to develop a python program and run it. The simplest way is type the program in Notepad or any Editor available in the OS, save the program with the file extension as py and Run it.

 

To Run a Python Program we have to open the command Window (Click Windows button in Run a application type cmd and press enter ,this will open the command Window which is in DOS mode.)

 

Using cd (Change Directory) command go to the location  of your folder where the Python program has been saved and type.

 

py <filename.py>

 

This will start the Python Interpreter and run the Program, if there is any Error it will display that too.

 

It is also possible to write a Python program in an Intergrated Development Environment (IDE), such as Thonny, Pycharm, Netbeans , Atom , Sublime Text, Eclipse etc., which are particularly useful when managing larger collections of Python files. This requires separate installations of the software. The Default IDE that comes with Python Software is name IDLE (Integrated Development and Learning Environment), this is available in the Folder where the Python Software is Installed in the System. IDLE can be used in 2 ways one as Python Shell Window or as Python Edit Window. The Default setup is Shell window where you can directly execute and Python statements. To change it to Edit Window, go to shell window screen from the options menu select configure IDLE menu and in the displayed TABS, select window Tab and set at startup as open edit window option instead of open shell window and click ok, close the shell window and restart the IDLE application.

 

In Edit window we have the option of RUN menu where after saving a Python file we can Run it using Run Module menu or using the shortcut key F5, for the same.

 

 

Python Syntax Compared to other Programming Language

 

Python was designed for readability , and has some similarities to the English language with influence from mathematics.

 

Python uses new lines to complete a command , as opposed to other programming languages which often use semicolons or parentheses as end of Line or Blocks.

 

Python relies on indentation or using whitespace , to define scope or block; such as the scope of control statements, Functions and classes. Either use Tab key or 4 Spaces uniformly for indentation purpose. Once a statement block completes reverse to the older indentation. Thus the python Interpreter will understand the above statements form a Block of Statements. Other programming languages often use curly brackets for this purpose.

 

Declaration of variables or Function are not required in python, while in other languages it is mandatory.

 

Python Language does not require any start point and End point unlike other Languages. The program can be a single line or of pages together. Each statement is Interpreted and executed.

 

Example of a Python Program

 

print("Welcome to the World of Python!!!")

 

This will display the statement enclosed in quotation as such. Now let's discuss about Python Language in detail.