Python Introduction for Data Science

Posted on March 13, 2023
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PYTHON

  • Python is a general purpose, dynamic, interpreted, interactive, object oriented and high-level programming language.
  • It is a free open-source language.
  • It supports the oops principles as supported by c++, java
  • Like Perl programming, python source code is also available under the GNU General Public License (GPL)
  • Python is a modern powerful interpreted language with objects, modules, threads, exceptions, and automatic memory managements
  • It is a one-way language system. It does not support compilation. It supports only interpretation.

FEATURES OF PYTHON

  1. Simple and Easy
    • Python is a simple language and easy to learn
  2. Free / Open Source
    • Python language is freely available at the official web site.
    • Python is a free open-source language, means that everybody can use python without purchasing license
    • The source code is also available. Therefore, it is an open-source language
  3. Interpreted Language
    • Python is a one-way language system. It supports only interpreter.
    • Python is a dynamic and interpreted object-oriented scripting language
    • Python code is processed at runtime by the interpreter
    • No need to compile the source code before executing the programs
    • Interpreter executes the code line by line at a time.
  4. Interactive
    • We can execute python commands with help of python interactive interpreter
    • We can directly interact with python interpreter to write programs using python prompt
  1. Object Oriented
    • Python supports the features of both procedure-oriented programming and object oriented programming
    • It supports single and multiple inheritance
    • Polymorphism is supported via runtime interpretation 
  2. Multi-purpose Language
    • It supports the creation of web applications, windows GUI applications, database applications, etc, …
  3. Portable
    • Python codes are machine and platform independent
    • Python has been ported to several platforms
    • We can use python on linux, windows, mac, solaris, OS/2, BeOS, Palm OS, QNX, etc, …
  4. Embedded Language
    • It is possible to embed python codes within C/C++ codes and can be used as a scripting language
  5. Large Standard Library
    • Python has a large set of library collection and provides the rich set of built-in module and functions for rapid application development
  6. Data Structures Support
    • Python supports lot of data structures like lists, sets & dictionaries

PYTHON FAMILY

WHO USES PYTHON

  • Google
  • Amazon
  • Pinterest
  • Instagram
  • Facebook
  • Uber
  • Dropbox, etc,…

FIRST RELEASE

  • The first version of python (0.9.0) was released in 20th February 1991
  • Guido Van Rossum is the creator of python language.

PYTHON RELEASES

  • Python 1.0 released in 1994
  • Python 2.0 released in 2000
  • Python 3.0 released in 2008
  • Python 3.5 released in 2015
  • Python 3.6 released in 2016
  • Python 3.7 released in 2018
  • Python 3.8 released in 2019 
  • Python 3.9 released in 2020
  • Python 3.10 released in 2021 
  • Python 3.11 released in 2022 (current version)

FILE FORMAT

  • Python programs are saved with the “.py” extension.

PYTHON FLAVORS

  • Python has a lot of implementations like CPython, JPython, IronPython, etc,.
S.NIMPLEMENTATIONVIRTUAL MACHINELANGUAGE
1.CPythonCPythonVMC Language
2.JythonJVMJava
3.IronPythonCLRC#
4.RubyPythonRubyVMRuby

1. Cpython

  • The base of all these implementation (flavors) is CPython or more formally called as Python
  • It was developed (Written) in C language and is a bytecode interpreter (bytecodes are executed on CPython Virtual Machine)

2. Jython (JPython)

  • It is an implementation of the python targeting the java platform
  • It was developed (Written) in java and runs on java virtual machine (JVM)

 3. IronPython

  • It is an implementation of the python targeting the .NET framework
  • It was entirely written in c# and runs on .NET virtual machine (CLR)
  • IronPython can use .NET framework and python libraries, providing python developers with the power of the .NET framework

4. RubyPython

  • It is an implementation of the python targeting the ruby platform
  • It was developed (Written) in ruby and runs on ruby virtual machine (RubyVM)

PYTHON VERSION

  1. Python language has two versions. They are:
    • Python 2.x
    • Python 3.x

Python 2.x

  • Python 2.x is legacy
  • Python 2.x is no longer in development and all new features will be added in python 3

Python 3.x

  • Python 3.x is the present and future of the language

 Usage of Python

  • Python is used in various areas. They are
    • Web Development
    • Artificial Intelligence
    • Machine Learning
    • Neural Networks, Robotics
    • Natural Language Processing
    • Internet of Things (IOT)
    • Big Data, AI, NLP, IOT
    • Data Science
    • Data Analysis and Visualization
    • Desktop GUI Development
    • Game Development, etc,…

10 REASONS TO LEARN PYTHON

DIFFERENCE BETWEEN PYTHON AND JAVA

S.NPYTHONJAVA
1.Language Type: Python is a one-way language. It supports only interpretation and does not support compilationLanguage Type: Java is a two-way language system. It supports both compilation and interpretation
2.Type System: It supports dynamic typed system. No need to mention the data type in the creation of variables and methods
Ex.
i=99		Type System: It supports static typed system. Data type must be provided in the creation of both variables and methods
Ex.
int i=95;
3.Semicolon: No need to use semicolon at the end of the statement in pythonSemicolon: Semicolon is needed at the end of every statement in java
4.Python uses indentation to separate code into blocks
Ex.
def disp():
 print(“Hello World”)
Indentation also improves the readability of code		Java uses curly braces to define the start and end of each function and class definition
Ex.
public void disp()
{   
 // user code
}
5.Speed: Python is slower than java, because of interpreterSpeed: Java is faster than python
6.Database: Python’s database access layers are weaker than java’s JDBC. So that, it rarely used in enterprisesDatabase: Java Database Connectivity (JDBC) is most popular and widely used to connect with database
7.main() function:
main() is an optional section in python		main() function:
main() is an compulsory section in java
8.Filename:
Filename: .py extension		Filename:
Filename: .java extension

IDE [INTEGRATED DEVELOPMENT ENVIRONMENT] SUPPORT

  • Visual Studio IDE      → Python, IronPython
  • PyCharm IDE      →   Python
  • Eclipse IDE                →    Python
  • Sharp Develop IDE     →   IronPython
  • Netbeans IDE             →   Java Python

 Online Cloud IDE

  • Repl.it (http://repl.it/)   → Python

Editor

  • Visual Studio Code (VSC)   →    Python

PYTHON APPLICATION TYPES

  • Python supports various types of applications

1. Console Application

  • Creating an application without any graphical component, that is called as console application

2. Desktop GUI Application

  • Creating an application, with use of graphical components is called as windows GUI Application (windows forms application)
  • It is an offline application: possible to run the windows GUI application in a particular machine at a time
  • Python supports the windows GUI application with help of GUI frameworks
  • Popular Python Window GUI Frameworks
    • Kivy, PyQT
    • Tkinter, WxPython
    • PyGUI
    • PySide.

3. Web GUI Application

  • Creating an application, with use of web graphical components is called as web GUI application (Internet application)
  • It is an online application: possible to run the web application in all machine at a time via internet access
  • Python is used to build server-side web applications (dynamic web applications)
  • Python supports the internet or web GUI application with help of GUI frameworks
  • Popular Python Web GUI Frameworks
    • Django
    • Flask
    • Pyramid
    • TurboGears
    • Web2Py, etc,…

4. Database Application

  • Creating an application, with use of database components that is called as database application
  • Python supports database applications. It supports various databases like Sqlite, MySQL, Oracle, Sybase, PostgreSQL, etc, …
  • Popular open-source databases
  1. Sqlite DB
  • It is built-in database (embedded in python language)
  • It stores the data in a single file.
  • It is very easy to connect sqlite database
  1.  PostgreSQL
  • It is an object relational database management system
  1. MongoDB
  • It is free open source, cross platform database
  • It is a NoSQL database
  • It is a document-based database
  1. MySQL
  • It is open-source RDBMS
  • It is commonly used for web applications.

5. Business Application

  • Python is used to build business applications like ERP and E-commerce Systems
  • Tryton is a high-level application platform

6. Multimedia Application

  • Python is used to develop multimedia applications like audio or video based applications

Example

7. Scientific and Numeric

  • Python is popular and widely used in scientific and numeric computing
  • Some of the useful library and packages:
    • SciPy
    • Pandas
    • IPython
  • SciPy is a group of packages of engineering, science and mathematics.

PYTHON PROGRAM STRUCTURE

  1. DOCUMENTATION SECTION
  • It is an optional section
  • It gives complete information about the python program like name of the program, author name, date, version & other details, etc, …
  • Python supports two comment statements.

Example

  1. SYSTEM MODULES
  • It is an optional section
  • It is used to load the predefined python libraries using “import” keyword
  • It is used to create different types of applications, algorithms, tools, OS, etc
  • The reserved keyword import is used to load entire module
  • Example:  sys, msvcrt, datetime, etc, …

Syntax

  import <package-name>

Example

  import msvcrt

  import exceptions

  import datetime

  1. EXECUTABLE SECTION
  • It is a mandatory section
  • Python code needs at least one executable statement to start the program execution
  • In python, execution always starts from top to bottom order.

Example

   print(“Good Morning”)

  1. FUNCTION SECTION
  • It is an optional section
  • It is used to execute group of statements
  • In python, the function is created with the help of reserved keyword def.
  1. CLASS SECTION
  • It is an optional section
  • Collection of variables and methods are grouped together into a single entity called as class
  • All the variables, methods in the classes are public by default
  • Classes are defined using “class” keyword
  • It is an important to note that, class should be terminated by the colon (:) operator
  • It also supports constructors (parameter & parameter less types)
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