• Python is not a program, it’s something like reading English Statements.

Introduction:

What is Python?

  • Python is a general-purpose high-level programming language. It is a language which can be used to develop an application. So it can be called as programming language.
  • Python is also an Interpreted programming language.
  • Python High-level programming language nothing but it’s programmer-friendly language.

Scope of the language

  • Python is not specific to a particular area, we can use any type of applications like desktop, web, etc.

History

Python was developed by Guido Van Rossum in 1989 while working at NRI(National Research Institute of Netherlands).But officially Python was made available to the Public in 1991. The official date of Birth for python is: Feb 20th 1991.C, Java are Statically Typed Programming where as Python is a Dynamically Typed Programming Language.

Python Borrows functional Programming features From C,OOP features From C++,Scripting languages features from Perl and shell script,Modular programming features from modular-3. Python is an all-rounder means is everything because it will support all programming language features.Most of the syntax is used in python and is borrowed from C and ABC programming language.

Applications of python

Python can be used in various fields such as,

  • Desktop Application
  • Web Applications
  • Database Applications
  • Networking Applications
  • Games
  • Data Analysis
  • Machine Learning
  • AI
  • For IoT Applications…
  • Deep Learning
  • Neural Network
  • Many companies such as Google, Facebook,Dropbox,Instagram,NASA uses python language for programming.

Features of Python

  • Simple and easy to learn,Freeware and Open Source,High-Level language
  • Platform Independent language
  • Portable language
  • Interpreted language
  • Dynamically typed language
  • Both object-oriented and procedure-oriented programming language
  • Extensible language
  • Embedded language
  • Extensive Library

Limitations Of Python:

  • Performance-wise Slower
  • Mobile Applications
  • Python is not suitable for large scales enterprise applications.. like Bank and telecom applications

Flavors of python

  • CPython
  • JPython or Jython
  • IronPython
  • Rubypython
  • AnacondaPython
  • Pypy-PVM-JIT(Just In Time) Compiler.

Python Versions

  • Python 0.9 –1991
  • Python 1.0 –1994
  • Python 2.0 — 2000
  • Python 3.0 — 2008

For example Print “hello” valid in python-2 but invalid in python-3, Print(“hello”) valid in python-3.

Elements of Python

Identifiers:

  • A name in python programming is called Identifier.
  • It can be a variable name, function name, class name, and module name.
  • Identifier refers to the name given to entities such as variables, functions, class, etc.

Example:   a=10   # ‘a’ is a variable name
Sum(a,b) # calling function

Rules for Identifiers:

  • Name contains alphabet symbols(both upper and lower case), digits(0—9), ‘_’ underscore.
  • Ex: man, easy2share, back_to_back
  • The name should starts with Alphabet or underscore but not digits.
  • Ex: total123 –> Valid
    2morrow –> Invalid
  • Identifiers are case sensitive. Of course, Python language is case sensitive programming language.
  • Ex: total = 10
    TOTAL = 99
    Print(total) # 10
    Print(TOTAL) # 99
  • Keywords are not used as identifier.
  • Ex: if, else, for –> Invalid
  • White spaces and special characters are not allowed.
  • Ex: Man power –> Invalid
    Ca$h –> Invalid
  • There is no limit on the length of a variable name.
  • Ex: giveanynamewithmorenumberofcharacter –>valid
    Man_power –> valid
    _pay –> valid
    Net pay –> Invalid
    Ca$h –> Invalid
    2morrow –> Invalid
    _net_pay_ –> Valid
    if –> Invalid
    def –> Invalid
    for –>Invalid
    easy2share –> Valid

Keywords:

  • Keywords are also known as Reserve words, they have predefined meaning in Python and these words cannot be changed by the user.
  • Keywords contain only alphabet symbols.
  • All keywords are lower case except the following three keywords.

  • True, False, None
  • There are 33 reserved words are there in Python

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