Python final presentation kirti ppt1

Python3 Programming
Language
10/2/2020

Presentation Outline
10/2/2020
Python Overview
Python Data Types
Python Control Structures
Python Inputoutput
Python Functions
Python File Handling
Python Exception Handling
Python Modules
Python Classes
Python vs. Java Examples
Python Useful Tools
Who uses Python?

What is Python?
10/2/2020
Python is a high-level programming language which is:
 Interpreted: Python is processed at runtime by the interpreter.
 Interactive: You can use a Python prompt and interact with the interpreter
directly to write your programs.
 Object-Oriented: Python supports Object-Oriented technique of
programming.
 Beginner’s Language: Python is a great
language for the beginner-level programmers and supports
the development of a wide range of applications.

History of Python
10/2/2020
 Python was conceptualized by Guido Van Rossum in the late
1980s.
 Rossum published the first version of Python code (0.9.0) in
February 1991 at the CWI (Centrum Wiskunde & Informatica)
in the Netherlands , Amsterdam.
 Python is derived from ABC programming language, which is a
general-purpose programming language that had been
developed at the CWI.
 Rossum chose the name "Python", since he was a big fan of
Monty Python's Flying Circus.
 Python is now maintained by a core development team at the
institute, although Rossum still holds a vital role in directing its
progress.

Python Versions
10/2/2020
Release dates for the major and minor
versions:
Python 1.0 - January 1994
 Python 1.5 - December 31, 1997
 Python 1.6 - September 5, 2000
Python 2.0 - October 16, 2000
 Python 2.1 - April 17, 2001
 Python 2.2 - December 21, 2001
 Python 2.3 - July 29, 2003
 Python 2.4 - November 30, 2004
 Python 2.6 - October 1, 2008
 Python 2.7 - July 3, 2010

Python Versions
10/2/2020
Release dates for the major and minor
versions:
Python 3.0 - December 3, 2008
 Python 3.1 - June 27, 2009
 Python 3.2 - February 20, 2011
 Python 3.4 - March 16, 2014

Python Features
10/2/2020
 Easy to learn, easy to read and easy to maintain.
 Portable:It can run on various hardware platforms and has the
same interface on all platforms.
 Extendable: You can add low-level modules to the Python interpreter.
 Scalable: Python provides a good structure and support for large
programs.
 Python has support for an interactive mode of testing and debugging.
 Python has a broad standard library cross-platform.
 Everythingin Python is an object:variables,functions, even code.
Every object has an ID, a type, and a value.

More Features ..
10/2/2020
 Python provides interfaces to all major commercial databases.
 Python supports functional and structured programming methods as
well as
OOP.
 Python provides very high-level dynamic data types and supports
dynamic
type checking.
 Python supports GUI applications
 Python supports automatic garbage collection.
 Python can be easily integrated with C, C++, and Java.

Useful Tools
10/2/2020
 Python IDEs
•Vim
•Eclipse with
PyDev
•Sublime Text
•Emacs
•Komodo Edit
•PyCharm

Useful Tools
10/2/2020
 Python Web
Frameworks
•Django
•Flask
•Pylons
•Pyramid
•TurboGears
•Web2py

What can I do with Python…?
 System programming
 Graphical User Interface Programming
 Internet Scripting
 Component Integration
 Database Programming
 Gaming, Images, XML , Robot and more
10/2/2020

Who uses python today…
 Python is being applied in real revenue-generating products
by real companies. For instance:
 Google makes extensive use of Python in its web search
system, and employs Python’s creator.
 Intel, Cisco, Hewlett-Packard, Seagate, Qualcomm, and IBM
use Python for hardware testing.
 ESRI uses Python as an end-user customization tool for its
popular GIS mapping products.
 The YouTube video sharing service is largely written in
Python
10/2/2020

Why do people use Python…?
 The following primary factors cited by Python users
seem to be these:
Python is object-oriented
 Structure supports such concepts as polymorphism,
operation overloading, and multiple inheritance.
It's free (open source)
 Downloading and installing Python is free and easy
Source code is easily accessible
10/2/2020

Organizations Use Python
10/2/2020
• Web Development :Google, Yahoo
• Games :Battlefield 2, Crystal Space
• Graphics :Walt Disney Feature Animation, Blender
3D
• Science :National Weather Service, NASA, Applied
Maths
• Software Development :Nokia, Red Hat, IBM
• Education :University of California-Irvine,
SchoolTool
• Government :The USA Central Intelligence Agency
(CIA)

It's powerful
 - Dynamic typing
 - Built-in types and tools
 - Library utilities
 - Third party utilities (e.g. Numeric, NumPy, SciPy)
 - Automatic memory management
It's portable
 - Python runs virtually every major platform used today
 - As long as you have a compatible Python interpreter
installed, Python programs will run in exactly the same
manner, irrespective of platform.
10/2/2020

Installing Python
 Python is pre-installed on most Unix systems, including
Linux
and MAC OS X
 But for in Windows Operating Systems , user can
download from the
https://www.python.org/downloads/
 - from the above link download latest version of
python IDE and install, recent version is 3.4.1 but
most of them uses version 2.7.7 only 10/2/2020

Installation of Python inWindows
• Go to Download Python page on the official site
(https://www.python.org/downloads/) and click Download
Python
3.6.5 (You may see different version name)
• When the download is completed, double-click the file and
follow the instructions to install it.
• When Python is installed, a program called IDLE is also
installed along with it. It provides graphical user interface to
work with Python.

• Open IDLE, Write the following code below and press enter.
print("Hello, World!")
• To create a file in IDLE, go to File > New Window (Shortcut:
Ctrl+N).
• Write Python code and save (Shortcut: Ctrl+S) with .py file
extension like: hello.py or your-first-program.py
print("Hello, World!")
• Go to Run > Run module (Shortcut: F5) and you can see the
output.

Python final presentation kirti ppt1

Basic Syntax
10/2/2020
 Indentation is used in Python to delimit blocks. The number of
spaces is variable, but all statements within
the same block must be
indented the same amount.
 The header line for compound statements, such as if, while,
def, and
class should be terminated with a colon ( : )
 The semicolon ( ; ) is optional at the end of statement.
 Printing to the Screen:
 Reading Keyboard Input:
 Comments
•Single line:
•Multiple lines:
 Python files have extension
.py
Error
!

Few Important Things toRemember
• To represent a statement in Python, newline (enter) is used.
• Use of semicolon at the end of the statement is optional
(unlike languages like C/C++)
• In fact, it's recommended to omit semicolon at the end of
the statement in Python
• Instead of curly braces { }, indentations are used to represent a
block

Python Keywords
• Keywords are the reserved words(can not be used as a
identifier) in Python
• Are case sensitive

Python Identifiers
• Name given to entities like class, functions, variables etc. in
Python
• Rules for writing identifiers
• Can be a combination of letters in lowercase (a to z) or uppercase (A
to Z) or digits (0 to 9) or an underscore (_)
• myClass, var_1 and print_this_to_screen, all are valid examples
• Cannot start with a digit
• 1variable is invalid, but variable1 is perfectly fine
• Keywords cannot be used as identifiers
• Cannot use special symbols like !, @, #, $, % etc. in our identifier
• Can be of any length.

Variables
10/2/2020
 Python is dynamically typed. You do not
need to declare variables!
 The declaration happens automatically
when
you assign a value to a variable.
 Variables can change type, simply by
assigning them a new value of a different
type.
 Python allows you to assign a single value to
several variables simultaneously.
 You can also assign multiple objects to
multiple variables.

Things to careabout
• Python is a case-sensitive language.
• Variable and variable are not the same.
• Multiple words can be separated using an
underscore, this_is_a_long_variable
• Can also use camel-case style of writing, i.e., capitalize
every first letter of the word except the initial word without
any spaces
• camelCaseExample

Python Statement
• Instructions that a Python interpreter can execute are
called statements.
• Two types
• Single line statement:
• For example, a = 1 is an assignment statement
• Multiline statement:
• In Python, end of a statement is marked by a newline character.
• So, how to make multiline statement?

• Technique1:
• make a statement extend over multiple lines with the line
continuation character ().
• For example:
a = 1 + 2 + 3 +
4 + 5 + 6 +
7 + 8 + 9

• Technique2:
• make a statement extend over multiple lines with the
parentheses ( )
• For example:
a=(1+2+3+
4+5+6+
7+8+9)

• Technique3:
• make a statement extend over multiple lines with the brackets [ ] and
braces {
}.
• For example:
colors = ['red',
'blue',
'green']

• We could also put multiple statements in a single line
using semicolons, as follows
a=1;b=2;c=3

Python Indentation
• Most of the programming languages like C, C++, Java use
braces { } to define a block of code
• Python uses indentation
• A code block (body of a function, loop etc.) starts with
indentation and ends with the first un-indented line

Error due to incorrectindentation

DataTypes
• In python data types are classes and variables are instance
(object) of these classes
• Different types of data types in python are:
• Python numbers
• Python lists
• Python tuples
• Python strings
• Python sets
• Python dictionary

Numbers
10/2/2020
 Numbers are Immutable objects in Python that cannot change their values.
 There are three built-in data types for numbers in Python3:
• Integer (int)
• Floating-point numbers (float)
• Complex numbers: <real part> + <imaginary part>j (not used much in Python
programming)
 Common Number Functions
Function Description
int(x) to convert x to an integer
float(x) to convert x to a floating-point number
abs(x) The absolute value of x
cmp(x,y) -1 if x < y, 0 if x == y, or 1 if x > y
exp(x) The exponential of x: ex
log(x) The natural logarithm of x, for x> 0
pow(x,y) The value of x**y
sqrt(x) The square root of x for x > 0

Strings
10/2/2020
 Python Strings are Immutable objects that cannot change their
values.
 You can update an existing string by (re)assigning a variable to another string.
 Python does not support a character type; these are treated as strings of length
one.
 Python accepts single ('), double (") and triple (''' or """) quotes to denote string
literals.
 String indexes starting at 0 in the beginning of the string and working their way
from -1
at the end.

Python Strings
• use single quotes or double quotes to represent strings.
• Multi-line strings can be denoted using triple quotes, ''' or
""".
• Example:
s = "This is a
string" s = '''a
multiline
string’’’
• Strings are also immutable.

Strings
10/2/2020
 String Formatting
 Common String Operators
Assume string variable a holds 'Hello' and variable b holds
'Python’Operator Description Example
+ Concatenation - Adds values on either side of the operator a + b will give
HelloPython
* Repetition - Creates new strings, concatenating multiple
copies of
the same string
a*2 will give HelloHello
[ ] Slice - Gives the character from the given index a[1] will give
e a[-1] will
give o
[ : ] Range Slice - Gives the characters from the given range a[1:4] will give ell
in Membership - Returns true if a character exists in the given
string
‘H’ in a will give True

Strings
10/2/2020
 Common String
MethodsMethod Description
str.count(sub,
beg=
0,end=len(str))
Counts how many times sub occurs in string or in a substring of
string if starting index beg and ending index end are given.
str.isalpha() Returns True if string has at least 1 character and all
characters are alphanumeric and False otherwise.
str.isdigit() Returns True if string contains only digits and False otherwise.
str.lower() Converts all uppercase letters in string to lowercase.
str.upper() Converts lowercase letters in string to uppercase.
str.replace(old, new) Replaces all occurrences of old in string with new.
str.split(str=‘ ’) Splits string according to delimiter str (space if not
provided) and returns list of substrings.
str.strip() Removes all leading and trailing whitespace of string.
str.title() Returns "titlecased" version of string.
 Common String
Functions
str(x) :to convert x to a string
len(string):gives the total length of the
string

Lists
10/2/2020
 A list in Python is an ordered group of items or elements, and these list
elements don't have to be of the same type.
 Python Lists are mutable objects that can change their values.
 A list contains items separated by commas and enclosed within square brackets.
 List indexes like strings starting at 0 in the beginning of the list and working their
way from -1 at the end.
 Similar to strings, Lists operations include slicing ([ ] and [:]) , concatenation
(+),
repetition (*), and membership (in).
 This example shows how to access, update and delete list elements:
 access
 slice
 update
 delete

Python List
• Ordered sequence of items
• Can contain heterogeneous data
• Syntax:
• Items separated by commas are enclosed within
brackets [ ]
• Example: a= [1,2.2,'python']

Extracting elements from thelist

• Note: Lists are mutable, meaning, value of elements of a list
can be altered.

Lists
10/2/2020
 Lists can have sublists as elements and these sublists may contain other
sublists
as well.
 Common List
Functions Function Description
cmp(list1, list2) Compares elements of both lists.
len(list) Gives the total length of the list.
max(list) Returns item from the list with max value.
min(list) Returns item from the list with min value.
list(tuple) Converts a tuple into list.

Lists
10/2/2020
 Common List
MethodsMethod Description
list.append(obj) Appends object obj to list
list.insert(index,
obj)
Inserts object obj into list at offset index
list.count(obj) Returns count of how many times obj occurs in
list
list.index(obj) Returns the lowest index in list that obj appears
list.remove(obj) Removes object obj from list
list.reverse() Reverses objects of list in place
list.sort() Sorts objects of list in place
 List Comprehensions
Each list comprehension consists of an expression followed by a for
clause.
 List comprehension

Tuples
10/2/2020
 Python Tuples are Immutableobjects that cannot be changedonce theyhave
been
created.
 A tuple contains items separated by commas and enclosed in parentheses instead
of square brackets.

access
 No update
 You can update an existing tuple by (re)assigning a variable to another tuple.
 Tuples are faster than lists and protect your data against accidental changes to
these data.
 The rules for tuple indices are the same as for lists and they have the same
operations,
functions as well.
 To write a tuple containing a single value, you have to include a comma, even
though there is only one value. e.g. t = (3, )

PythonTuple
• Same as list but immutable.
• Used to write-protect the data
• Syntax:
• Items separated by commas are enclosed within
brackets ( )
• Example:
• t = (5,'program', 1+3j)

Dictionary
10/2/2020
 Python's dictionaries are kind of hash table type which consist of key-
value pairs
of unordered elements.
• Keys : must be immutable data types ,usually numbers or strings.
• Values : can be any arbitrary Python object.
 Python Dictionaries are mutable objects that can change their values.
 A dictionary is enclosed by curly braces ({ }), the items are separated by
commas, and each key is separated from its value by a colon (:).
 Dictionary’s values can be assigned and accessed using square braces
([]) with a key to obtain its value.

Dictionary
10/2/2020
 This example shows how to access, update and delete dictionary
elements:
 The
output:

Dictionary
10/2/2020
 Common Dictionary Functions
• cmp(dict1, dict2) : compares elements of both dict.
• len(dict) : gives the total number of (key, value) pairs in the
dictionary.
 Common Dictionary Methods
Method Description
dict.keys() Returns list of dict's keys
dict.values() Returns list of dict's values
dict.items() Returns a list of dict's (key, value) tuple pairs
dict.get(key,
default=None)
For key, returns value or default if key not in dict
dict.has_key(key) Returns True if key in dict, False otherwise
dict.update(dict2) Adds dict2's key-values pairs to dict
dict.clear() Removes all elements of dict

Python Set
• Unordered collection of unique items
• defined by values separated by comma inside
braces { }

• Set have unique values. They eliminate
duplicates.
• Example:

• Since, set are unordered collection, indexing has no
meaning.
• Hence the slicing operator [] does not work.
• Example:

Python Control
Structures
10/2/2020

Conditionals
10/2/2020
 In Python, True and False are Boolean objects of class 'bool' and they are
immutable.
 Python assumes any non-zero and non-null values as True, otherwise it is
False value.
 Python does not provide switch or case statements as in other languages.
 Syntax:
if Statement if..else Statement if..elif..else Statement
 Example:

Conditionals
10/2/2020
 Using the conditional expression
Another type of conditional structure in Python, which is very convenient and easy
to read.


Loops
10/2/2020
 The For
Loop
 The while
Loop

Loops
10/2/2020
Loop Control Statements
 break :Terminates the
loop
statement and transfers execution to the
statementimmediately following the
loop.
 continue:Causes the loop to skip the remainder of its body and immediately
retest its condition prior to reiterating.
 pass:Used when a statement is required syntactically but you do not want
any
command or code to execute.

Functions
10/2/2020
 Function
Syntax
 Function Arguments
You can call a function by using any of the following types of
arguments:
• Required arguments: the arguments passed to the function in
correct positional order.
• Keyword arguments: the function call identifies the arguments
by the parameter names.
• Default arguments: the argument has a default value in the
function declaration used when the value is not provided in the
function call.

Functions
10/2/2020
• Variable-length arguments: This used when you need to process unspecified
additional
arguments. An asterisk (*) is placed before the variable name in the function
declaration.

Python File
Handling
10/2/2020

File Handling
10/2/2020
 File
opening
fileObject = open(file_name [, access_mode][,
buffering])
Common access modes:
• “r” opens a file for reading only.
• “w” opens a file for writing only. Overwrites the file if the file exists.
Otherwise, it creates a new file.
• “a” opens a file for appending. If the file does not exist, it creates a
new file for writing.
 Closing a
file
fileObject.close
()
The close() method flushes any unwritten information and closes the file
object.

File Handling
10/2/2020
 Reading a
file
fileObject.read([count])
• The read() method reads the whole file at once.
• The readline() method reads one line each time from
the file.
• The readlines() method reads all lines from the file in a
list.
 Writing in a
file
fileObject.write(string)
The write() method writes any string to an open
file.

Python Exception
Handling
10/2/2020

Exception Handling
10/2/2020
 Common Exceptions in Python:
NameError - TypeError - IndexError - KeyError -
Exception
 Exception Handling Syntax:
 An empty except statement can catch any exception.
 finally clause: always executed before finishing try
statements.


Modules
10/2/2020
 A module is a file consisting of Python code that can define functions, classes and
variables.
 A module allows you to organize your code by grouping related code which
makes the
code easier to understand and use.
 You can use any Python source file as a module by executing an import
statement
 Python's from statement lets you import specific attributes from a module into the
current namespace.
 import * statement can be used to import all names from a module into the
current namespace

Python Object
Oriented
10/2/2020

Python Classes
10/2/2020
Output

 Class variable
 Class
constructor

Python Classes
10/2/2020
 Built-in class functions
• getattr(obj, name[, default]) : to access the attribute of object.
• hasattr(obj,name) : to check if an attribute exists or not.
• setattr(obj,name,value) : to set an attribute. If attribute does not exist,
then it would be created.
• delattr(obj, name) : to delete an attribute.
 Data Hiding You need to name attributes with a double underscore
prefix, and those
attributes then are not be directly visible to outsiders.

Python vs. Java
Code Examples
10/2/2020

Python vs. Java
10/2/2020
 Hello
World
Java Pytho
n
 String
Operations
Java Pytho
n

Python vs. Java
10/2/2020
 Collectio
ns
Java
Pytho
n

Python vs. Java
10/2/2020
 Class and
Inheritance
Java
Pytho
n


References
10/2/2020
1 Python-course.eu, 'Python3 Tutorial: Python Online Course', 2015. [Online]. Available:
http://www.python-course.eu/python3_course.php.
2www.tutorialspoint.com, 'Python tutorial', 2015. [Online].
Available: http://www.tutorialspoint.com/python/index.htm.
3 Wikipedia, 'History of Python', 2015. [Online]. Available:
https://en.wikipedia.org/wiki/History_of_Python#Version_release_dates.
4Docs.python.org, 'What's New In Python 3.0’, 2015. [Online].
Available: https://docs.python.org/3/whatsnew/3.0.html.
5Sebastianraschka.com, 'Python 2.7.x and Python 3.x key differences', 2015. [Online].
Available: http://sebastianraschka.com/Articles/2014_python_2_3_key_diff.html.
6Programcreek.com, 'Java vs. Python: Why Python can be more productive?', 2015.
[Online]. Available: http://www.programcreek.com/2012/04/java-vs-python-why-python-
can-be-more- productive/.
ByTahaniAlmanie |CSCI5828

References
10/2/2020
7Stsdas.stsci.edu, 'A Quick Tour of Python', 2015. [Online].
Available: http://stsdas.stsci.edu/pyraf/python_quick_tour.html.
8Lynda.com - A LinkedIn Company, 'Python 3 Essential Training | Lynda.com Training',
2015. [Online]. Available: http://www.lynda.com/Python-3-tutorials/essential-
training/62226-2.html.
9Pymbook.readthedocs.org, 'Welcome to Python for you and me — Python for you
and me 0.3.alpha1 documentation', 2015. [Online]. Available:
http://pymbook.readthedocs.org/en/latest/index.html.
10 Code Geekz, '10 Best Python IDE for Developers | Code Geekz', 2014. [Online].
Available:
https://codegeekz.com/best-python-ide-for-developers/.
11K. Radhakrishnan, 'Top 10 Python Powered Web Frameworks For Developers',
Toppersworld.com, 2014. [Online]. Available: http://toppersworld.com/top-10-python-powered-
web- frameworks-for-developers/.
12Wiki.python.org, 'OrganizationsUsingPython - Python Wiki', 2015. [Online].
Available: https://wiki.python.org/moin/OrganizationsUsingPython. ByTahaniAlmanie |CSCI5828

Python final presentation kirti ppt1

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