1. Python Introduction

1. Introduction to Python - 20 min read

What is Python?
Where are all python is using?
History of Python?
Why the name was python?
Python versions
Python supports Functional and OOPs as well
Solving a few requirements by using C, Java and python
Machine language
Translator
Interpreter
Compiler
Python keywords (33)
Features of Python
Flavors of Python
Python versions
Programs

1. Python Introduction

1. What is Python?

Python is a general purpose and high-level programming language.

All companies are using a python programming language to develop the applications, testing and maintenance etc.
There are mainly two types of programming languages in this world,

High level

Human readable language.
Easy to understand

Low level

Machine-readable language like bits (1’s and 0’s form)

2. Where are all python is using at the application level?

To develop,

Standalone applications

An application which needs to install on every machine to work with that application.

Web applications

An application which follows client-server architecture.
The client is a program, which sends a request to the server.
The server is a program, mainly it can do three things,

Captures the request from the client
Process the request
Sends the response to the client

Database applications.
To process a huge amount of data.

Hadoop
Spark.

Machine learning.
Artificial Intelligence.
Data science.
Network servers.
IOT
Application scripting etc.

3. History of Python?

Python was created by Guido Van Rossum in the year of 1989.
It is open source software means we can download freely and customize the code as well.

4. Why the name was python?

A TV show Monty Python’s Flying Circus was very much a popular fun show in the 1970s.
So, Guido like this show and given this name to his programming language.

5. Python versions

The first version was released in Feb 20^th, 1991.
Current version 3.6.x release Dec 23^rd, 2016.

6. Python supports

Functional programming.
Object-oriented programming approach
Nowadays to fulfill the requirement both are required.

Python = Functional programming + Object-oriented programming

7. Which companies are using Python?

Currently, all companies are using python.

8. To solve any requirement,

Initial languages like C, Pascal or FORTRAN follows a functional approach.
C++, Java and dot net follows the object-oriented approach.
Python follows both functional and object-oriented approaches

Requirement 1 : Java programs to print, Welcome to Java programming

Java program : HelloWorld.java

Requirement	Program prints Welcome to Java programming
output	Welcome to Java programming

class HelloWolrd

{

public static void main (String args [])

{

System.out.println(“Welcome to Java programming”);

}

Output

Welcome to Java programming

To write Java code at least you should write a single class.

C program : HelloWorld.c

Requirement	Program to print, Welcome to C programming
output	Welcome to C programming

#include<stdio.h>

{

void main ()

{

printf(“Welcome to C programming”);

}

Output

Welcome to C programming

To write C code at least you should write a function

Python program : HelloWorld.py

Requirement	Program to print, Welcome to Python programming
output	Welcome to Python programming

print(“Welcome to Python programming”)

Output

Welcome to Python programming

Above python program is a simple approach and more understandable even for nursery student also.

Requirement 2: Take two numbers and apply addition logic.

So, the above requirement we are going to see by using Java, C, and python

Java program : Addition.java

Requirement	Program prints to add two number in Java
output	30

class Addition

{

public static void main (String args[])

{

int a = 10;

int b = 20;

System.out.println(a+b);

}

Output

To write Java code at least you should write a single class to express logic.
Sometimes this makes program lengthy and consumes more time.

C program : Addition.c

Requirement	Program prints to add two number in Java
output	30

#include<stdio.h>

{

void main()

{

int a = 10;

int b = 20;

println(a+b);

}

Output

To write C code at least you should write a function to express logic.
Sometimes this also makes program lengthy and consumes more time.

Python program : addition.py

Requirement	Program prints to add two number in Java
output	30

a = 10

b = 20

print(a+b)

Internal representation

Output

Above python code is simple approach and more understandable even for non-techy also.

Make a note:

Semicolons are mandatory in C and Java programming languages.
In python, semicolons are not required.

Points to make a note

In many programming languages to write a program,

We need to create the structure with symbols in a certain order.
Next step is, we need to write logic.
In python we can see the very informative code by writing a simple way.

In Python programming a single line, which prints a short message.
It’s a very informative example of Python’s syntax.

9. Machine language

Representing the instructions and data in the form of bits (1’s and 0’s) is called machine code or machine language.
Example to add two numbers then the machine will convert these number into bits by division with 2.

Ex : 12 + 14 = 26

2 | 12

| 6 - 0 Reminder

| 3 - 0 Reminder

| 1 - 1 Reminder

12 == 1100 Take the digits from bottom to top digits

2 | 14

| 7 - 0 Reminder

| 3 - 1 Reminder

| 1 - 1 Reminder

14 == 1110 Take the digits from bottom to top digits

Internally these bits values will be adding and generate the sum result as 26

1.9 Translator

A Translator is a program that converts any computer programs into machine code.
There is ‘n’ number of translators are existing but for us we need to understand 2 types of translators.

1. Interpreter

An interpreter is a program, it can convert the program by line by line.

2. Compiler

The compiler is a program converts the entire program in a single step.

10. Python Reserved words or keywords (33)

The words which are reserved to do a specific functionality is called reserved words are keywords.
In Python total 33 keywords are available

Make a note:

All keywords in Python contains only alphabet symbols.
All keywords are in lowercase except 3 those are,

True
False
None

10.1 To see all these reserved words from the python shell

>>> import keyword

>>>keyword.kwlist

['False', 'None', 'True', 'and', 'as', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'nonlocal', 'not', 'or', 'pass', 'raise', 'return', 'try', 'while', 'with', 'yield']

Make a note:

Program implementing by using notepad and executing command prompt is best practice

Program To see all python keywords

Name demo1.py

import keyword

print(keyword.kwlist)

Output

Note:

keyword is a module in python

11. Features of python

1.Simple

Python syntax is very easy.
Developing and understanding of python is very easy than others.

2.Open source

We can download freely and customize the code as well

3.High-level language

There are two types of languages,

Low level

Machine code instructions, difficult to learn programmer.

High level

English words with syntax, the programmer can learn easily.

4. Dynamically typed

Dynamically type will be assigned to data.

5.Platform independent

Python programs are not dependent on any specific operating systems.
We can run on all operating systems happily.

6.Portable

If a program gives the same result on any platform then it is a portable program.
Python used to give the same result on any platform.

7.Procedure and object-oriented

Python supports both procedural and object-oriented features.

8. Huge library

Python has a big library to fulfill the requirements.

9. Database connectivity

Python provides interfaces to connect with all major databases like Oracle, MySQL

10. Batteries included

Python provides inbuilt libraries called batteries,
Some of them are below,

Boto

Amazon web services library

MySQL -connector-python

To connect with MySQL

NumPy

To process arrays

Pandas

powerful data structures for data analysis, time series and statistics

so many others…

12. Different flavors of python

Flavors of python refer to the different types of python compilers.
These are useful to integrate various programming languages.

1. CPython

Standard python compiler implemented in C language.
This is the python software being downloaded and used by the programmers directly.

2. Jython

Initially called as JPython, later renamed to Jython.
Designed to run on Java program.

3. IronPython

Designed for .NET framework.

4. PyPy

The main advantage of PyPy is performance will be improved because JIT compiler is available inside PVM.

5. RubyPython

This is a bridge between Ruby and python interpreters.
It encloses a python interpreter inside Ruby application.

6. AnacondaPython

Anaconda is a free and open source Python programming languages.
This is mainly for data science and machine learning related applications (large-scale data processing, predictive analytics, scientific computing).
This aims to simplify package management and deployment.

13. Python Versions

Python 1.0V introduced in Jan 1994
Python 2.0V introduced in October 2000
Python 3.0V introduced in December 2008.
The current version is 3.6

Make a note

Python 3 won't provide backward compatibility to Python2 i.e. there is no guarantee that Python2 programs will run in Python3.

Monday, 29 April 2019

1. Python Introduction

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