Python Notes Edition 3

Freeware:

=>If any software downloaded Freely and that Software comes under Freeware

Examples: Python, Java-----

-----------------------------------------------------------------------------------------------

Open Source:

=>The standard Name of Python Software is "CPYTHON".

=>Many Software companies came forward and Customized CPYTHON and developed their own

in-house tools.

=>The Customized Versions of CPYTHON are called "Python Distributions".

=>Some of the Python Distributions are.

1. JPython OR Jython----->Used for Running Java Based Applications

2 Iron Python OR IPython--->used to run C#.net Applications

3. Ruby Python ------>Used to Run Ruby Applications

4. Micro Python----->Used to run / develop Micro Controller Applications

5. Ankonda Python---->used to Run Big data / Hadoop Based Applications

5. StackLess Python--->Used for Concurrency Applications...etc

3. Platform Independent Lang

=====================================================

=>A Platform is nothing but Type of OS being Used to run Application / Program.

=>In this context, we have two types of Programming languages. They are

1. Platform Dependent Lang

2. Platform Independent Lang

--------------------------------------------------------------------------

1. Platform Dependent Lang

--------------------------------------------------------------------------

=>In Platform Dependent Lang, Data Types differes from One OS to Another OS.

Example: C,C++....etc

--------------------------------------------------------------------------

3. Platform Independent Lang

--------------------------------------------------------------------------

=>In Platform Independent Lang, Data Types memory remains Same on All Types OSes.

=>In Effective Platform Independent Lang, all types of Values will store in the form of OBJECTs and they can store Un-Limited amount of data

=>Hence java Object contains Size Restricted where Python Objects contains Un-limited Size and unlimited values can store.

NOTE: IN PYTHON ALL VALUES ARE STOREd IN THE OF OBJECTS.

Examples: Java, Python.

--------------------------------------------------------------------------

4. Dynamically Typed

==============================================

=>In IT, we have Two Types of Programming languages. They are

1. Static Typed Programming Languages

2. Dynamically Typed Programming Languages

-----------------------------------------------------------------------------------------------------------------------

1. Static Typed Programming Languages

-----------------------------------------------------------------------------------------------------------------------

=>In Static Typed Programming Languages, It is mandatory to Specify Variable Declaration for storing

Inputs in main memory of Computer.

Examples Statements:

---------------------------------

int x,y,z; // Variable Declaration--mandatory

x=10

y=30

z=x+y

Examples Lang: C, C++, Java, C#.net....etc

-----------------------------------------------------------------------------------------------------------------------

2. Dynamically Typed Programming Languages

-----------------------------------------------------------------------------------------------------------------------

=>In Dynamically Typed Programming Languages, depends on type of value we are assiging, whose data type automatoically / Implicitly assigned by Python Execution Environment

=> There is No Need to write Variable declaration in Dynamically Typed Programming Languages

Example Stmts:

---------------------

>>> a=100

>>> b=200

>>> c=a+b

===============================================

5. Interpreted Programming

===============================================

=>When we develop any python program, we must give some file name with an extension .py (File Name.py).

=>When we execute python program, two process taken place internally

a) Compilation Process

b) Execution Process.

=>In COMPILATION PROCESS, The python Source Code submitted to Python Compiler and It reads the source Code, Check for errors by verifying syntaxes and if no errors found then Python Compiler Converts into Intermediate Code called BYTE CODE with an extension .pyc (FileName.pyc). If erros found in source code then we get error displyed on the console.

=>In EXECUTION PROCESS, The PVM reads the Python Intermediate Code(Byte Code) and Line by Line and Converted into Machine Understable Code (Executable or binary Code) and It is read by OS and Processer and finally Gives Result.

=>Hence In Python Program execution, Compilation Process and Execution Process is taking place Line by Line conversion and It is one of the Interpretation Based Programming Language.

-------------------------------------------------------------------

Definition of PVM ( Python Virtual Machine )

--------------------------------------------------------------------

=>PVM is one program in Python Software and whose role is to read LINE by LINE of Byte Code and Converted into Machine Untestable Code (Executable or binary Code)

---------------------------------------------------------------------------------------------------------

6. High Level Programming

=======================================

=>In this context, we have two types of languages. They are

1. Low Level Programming Languages

2. High Level Programming Languages

-----------------------------------------------------------------

1. Low Level Programming Languages:

-----------------------------------------------------------------

=>In Low Programming Languages, data is always stored in the form of low level values such as Binary data, Octal Data and Hexa Decimal data. These Number System are not directly understandable end-users

Example : a=0b1010101010

b=0xBEE

c=0o23

-----------------------------------------------------------------

2. High Level Programming Languages

-----------------------------------------------------------------

=>In these languages, Internally, Even the programmer specifies the data in the form of Low Level Format such Binary data, Octal Data and Hexa Decimal data, automatically Python Programming Language Execution Environment Converts into High Level data, which is understandable by end-users . Hence Python is one of the High Level Programming Languages.

Examples:

----------------

>>> a=0b101010111110000

>>> b=0b10101111000

>>> print(a)-----------------------22000

>>> print(b)----------------------1400

>>> a=0xBEE

>>> print(a)-----------------------3054

>>> bin(22000)-----------------'0b101010111110000'

>>> hex(3054)----------------'0xbee'

======================================x================================

7. Robust (Strong)

======================================

=>Python is one of the Robust programming lang bcoz it provides "Exception handling" facility. If the

Python programmer uses Exception handling then Python Based Applications Becomes Robust.

-----------------------------------------

=>Definition of Exception

-----------------------------------------

=>All Runtime Errors are called Exception.

=>By default, All Programming Lang, when exception occurs then we get Technical Error Messages.

=>In Industry It is not recommended to generate technical Error Messages bcoz these messages are not understandable by End-users.

=>Industry is recommended to generate user-Friendly Error messages by using "Exception handling".

---------------------------------------------------------

=>Definition of Exception Handling

---------------------------------------------------------

=>The Process of Converting Technical Error Messages into user-freindly error messages is called

Exception Handling.

=========================================x========================================

======================================

9 Extensible and 10 Embedded

======================================

Extensible:

------------------

=>A programming is lang is said to be "Extensible" iff It provides Programming Faclities

to other languages

=>Example: Python Programming Provides its Programming Facilities to C,C+,Java..etc

and hence Python is one of the Extensible Programming Lang.

----------------------

Embedded:

----------------------

=>A programming Lang is said to be Embedded iff It takes the Programming Services of Other languaes.

=>For Example: Python Programming Embedded the Programming Services of C bcoz C is the Fastest Programming Lang.

=================================x===========================

Supports Third Party APIs Such as numpy, pandas, scipy, scikit, keras,

matplotlib, nlp..etc

==================================================

=>Most of the Supports Third Party APIs Such as numpy, pandas, scipy, scikit, keras,

matplotlib, nlp..etc are providing Easiness to Python programmer in the case Complex Maths Calculations(Numpy), Businness Analysis and Analytics (Pandas)..etc