BASICS OF PYTHON PROGRAMMING

1. PYTHON PROGRAMMING
UNIT
1
RESHMA R
ASSISTANT PROFESSOR
CSE, KAHE

2. OUTLINE
• PYTHON
• WHY PYTHON?- FEATURES
• ADVANTAGES
• APPLICATIONS
• TOOLS
• INSTALLATION

3. PYTHON
• Interpreter language, High level language, Dynamic, Garbage Collected language
• Developed by Guido Van Rossum in 1991
• Python Software Foundation
• Official Web Site: https://www.python.org
• Code Readability
• Simple Syntax
• Works quickly and effectively
VERSIONS: PYTHON 2 & PYTHON 3
2020- Python 2.7.15
2021- Python 3.9.7
2000- Python 2
2008- Python 3

4. WHY PYTHON?-FEATURES
• Object Oriented
• Free/Open Source
• Powerful
• Dynamic typing
• Built-in types and tools
• Library utilities
• Third party utilities (e.g. NumPy, sciPy)
• Automatic memory management
• Portable
• Easy to use and learn
• Interactive

5. ADVANTAGES
• Enhanced readability
• Uniform indents to delimit blocks of statements instead of curly brackets
• Free and distributed as open-source software
• Available to large programming community
• Support Python libraries for various applications such as web frameworks, mathematical
computing, and data science
• A cross-platform language
• Works on Windows, Linux, Mac, etc.
• Supports multiple programming paradigms
• Imperative, procedural, object-oriented, and functional programming styles
• An extensible language
• Additional functionality through modules and packages of other languages
• Integrated with other languages

6. APPLICATIONS
• Data Science
• Companies need business insights from mobile data, web data,
sensor data, etc.

7. TOOLS

8. INSTALLATION
• Available on https://www.python.org/downloads
• Installed on Windows, Linux, Mac OS and certain other platforms such as IBM
AS/400, iOS, Solaris, etc.
• Windows:
• Web-based installer
• Executable installer
• Embeddable zip files

15. • After successful installation
• Check the Python installation using command prompt
• type python --version or python -V and press
• If Python installed successfully
• Display the installed version
• C:>python --version
• Python 3.7.0

16. • Mac OS X
• https://www.python.org/downloads/mac-osx page.
• Download the latest version under the heading Python Releases for Mac OS X.
• Double click on the installer file to start the installation wizard.
• On the installation wizard, click on Continue a few times
• Until you're asked to agree to the software license agreement,
• Click on Agree and finish the installation.

17. • Linux
• Mostly come up with Python installation
• If Python 3.x is available, run the following command in the Linux terminal:
• $ which python3
• If available, it will return the path to the Python3 executable as
• /usr/local/bin/python3.
• To install Python on Ubuntu 18.04, Ubuntu 20.04 and above,
• Execute the following commands:
• $ sudo apt-get update
• $ sudo apt-get install python3.7 python3-pip

18. 3 STEPS
• Find the interpreter
• Write program
• Run and test

19. INTERACTIVE SHELL/SCRIPT

21. PRACTICE
• Lets learn through EXCERCISE

22. SYNTAX
• Set of rules - defines how a Python program will be written and interpreted
• For example – Grammar in English language

23. PYTHON LINE STRUCTURE
• Python program comprises logical lines
• NEWLINE token follows each
• Indicates the end of a logical line of Python code
• Interpreter ignores blank lines.
• >>> print("Hi
How are you?")
SyntaxError: EOL while scanning string literal
Error

24. PYTHON MULTILINE STATEMENTS
• Python does not mandate semicolons
• New line means a new statement
• Sometimes, need to split a statement over two or more lines
• to aid readability
a. Use a backward slash
• >>> print("Hi
how are you?")
b. Put the String in Triple Quotes
• >>> print("""Hi
how are you?""")
• Can distribute a statement without a string across lines.
• >>> a
=
10
>>> print(a)
Output: 10 instead a=10

25. PYTHON COMMENTS
• Declare a comment using an octothorpe (#)
• >>> #This is a comment
PYTHON DOCSTRINGS
• Documentation string
• Unlike comments, they are more specific
• As a comment, this Python Syntax is used to explain code.
>>> def func():
"""
This function prints out a greeting
"""
print("Hi")
>>> func()
Delimit a docstring using three double-quotes.

26. PYTHON INDENTATION
• Doesn’t use curly braces to delimit blocks of code
• Indent code under a function, loop, or class.
• >>> if 2>1:
print("2 is the bigger person");
print("But 1 is worthy too");
• Use 4 spaces or tab
PYTHON MULTIPLE STATEMENTS IN ONE
LINE
• Fit in more than one statement on one line.
• >>> a=7;print(a);

27. PYTHON QUOTATIONS
• Supports single quote and the double quote for string literals
• >>> print('We need a chaperone’);
• >>> print(“We need a chaperone”);
• >>> print(“We need a ‘chaperone’”);
>>> print(“We need a “chaperone””);
>>> print('We need a ‘chaperone’'); ERROR

28. PYTHON BLANK LINES
• If you leave a line with just whitespace, the interpreter will ignore it.
• Name of a program element - user-defined
• Python syntax uniquely identifies the element
• An identifier may only begin with A-Z, a-z, or an underscore(_).
• This may be followed by letters, digits, and underscores- zero or more.
• Python is case-sensitive. Name and name are two different identifiers.
• A reserved keyword may not be used as an identifier.
PYTHON IDENTIFIERS

29. LIST OF KEYWORDS

30. PYTHON VARIABLES
• It is assumed on the basis of the value it holds.
>>> x=10
>>> print(x)
OUTPUT: 10
>>> x='Hello'
>>> print(x)
OUTPUT: Hello
DISCUSS IN
DETAIL LATER…..

31. PYTHON STRING FORMATTERS
a. % Operator
 To format a string to contain text and values of identifiers
 Use %s where you want a value to appear
 After the string, put a % operator
 Mention the identifiers in parameters
Example:
>>> x=10; printer="HP"
>>> print("I just printed %s pages to the printer %s" % (x, printer))
Output:
I just printed 10 pages to the printer HP

32. b. Format Method
To format a string in a similar way
At the places, you want to put values
 Put 0,1,2,.. in curly braces.
Call the format method on the string
 Mention the identifiers in the parameters.
Example:
>>> x=10, printer=‘HP’, y=‘Printer’
>>>print("I just printed {0} pages to the printer {1} {2}".format(x, printer,y))
>>> print("I just printed {x} pages to the printer {printer}".format(x=10, printer='HP'))
Output:
I just printed 10 pages to the printer HP Printer

33. c. f-strings
• Write ‘f’ right before the string
• But outside the quotes used.
>>> print(f"I just printed {x} pages to the printer {printer}")
Output:
I just printed 10 pages to the printer HP