Python Introduction -

PYTHON INTRODUCTION

INTRODUCTION TO THE IDLE INTERPRETER (SHELL)

Python is a freeware that can be installed on your workstation or laptop.
The current version of is Python 3.9. (Release Date: Oct. 5, 2020).
Python can be downloaded from the https://www.python.org/downloads/
Website

After installation, shortcut for the python software will be available on the start menu. Select Start menu -> All Programs -> Python 3.9 -> IDLE Python 3.9 to invoke python IDE (Integrated Development Environment).

IDLE (Integrated Development and Learning Environment) is an IDE for Python. Python programs can also be executed in Python command line.

Program

A program performs a task in the computer. But, in order to be executed, a program must be written in the machine language of the processor of a computer. Unfortunately, it is extremely difficult for humans to read or write a machine language program. This is because a machine language is entirely made up of sequences of bits. However, high level languages are close to natural languages like English and only use familiar mathematical characters, operators and expressions. Hence, people prefer to write programs in high level languages like C, C++, Java, or Python. A high level program is translated into machine language by translators like compiler or interpreter.

About Python

Python is a high level programming language that is translated by the python interpreter. As is known, an interpreter works by translating line-byline and executing. It was developed by Guido-van-rossum in 1990, at the National Research Institute for Mathematics and Computer Science in Netherlands. Python doesn’t refer to the snake but was named after the famous British comedy troupe, Monty Python’s Flying Circus.

Python is Interpreted: Python is processed at runtime by the interpreter. You do not need to compile your program before executing it.
Python is Interactive: we can actually sit at a Python prompt and interact with the interpreter directly to write our programs.
Python is Object-Oriented: Python supports Object-Oriented style or technique of programming that encapsulates code within objects.

Application of python used in Search engine. In mission critical projects in Naza, in processing financial transaction at New york stock Exchange.

The following are some of the features of Python:

Python is an Open Source: It is freely downloadable, from the link “http:// python.org/”
Python is portable: It runs on different operating systems / platforms3
Python has automatic memory management
Python is flexible with both procedural oriented and object oriented programming
Python is easy to learn, read and maintain.
Python is Extendable. You can add low-level modules to the Python is Interpreted. These modules enable programmers to add to or customize their tools to be more efficient.
Python supports GUI applications that can be created and ported to many system calls, libraries and windows systems, such as Windows MFC, Macintosh, and the X Window system of Unix.
IT supports automatic garbage collection.
It can be easily integrated with C, C++, COM, ActiveX, CORBA, and Java.
It supports functional and structured programming methods as well as OOP.

It is very flexible with the console program, Graphical User Interface (GUI) applications, Web related programs etc.

Points to remember while writing a Python program

Case sensitive : Example – In case of print statement use only lower case and not upper case, (See the snippet below)

Punctuation is not required at end of the statement
In case of string use single or double quotes i.e. ‘ ’ or “ ”
Must use proper indentation. The screen shots given below show, how the value of “i” behaves with indentation and without indentation.