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  1. 1. Module-1 Getting Started with Python
  2. 2. LIVE On-line Class Class Recording in LMS 24/7 Post Class Support Module Wise Quiz and Assignment Project Work on Large Data Set Verifiable Certificate Slide 2 How it Works?
  3. 3. Slide 3Slide 3 Course Topics  Module 1 » Getting Started with Python  Module 2 » Sequences and File Operations  Module 3 » Deep Dive - Functions, Sorting, Errors and Exception Handling, Regular Expressions and Packages  Module 4 » Object Oriented Programming in Python  Module 5 » Debugging, Databases and Project Skeletons Module 6 » Machine Learning Using Python – I Module 7 » Machine Learning Using Python – II Module 8 » Introduction to Hadoop  Module 9 » Hadoop and Python  Module 10 » Web Scraping using Python and Project Work
  4. 4. Slide 4 Objectives Understand Python- an Object-oriented Programming Language. List the users of Python for Data Analytics. Define Identifiers and indentation. List Operations on Numbers and Operations on Strings. Run a Python Script. At the end of this module, you will be able to:
  5. 5. Slide 5 Python is a very-high-level dynamic object-oriented programming language. Python is easy to program and read. Similar to PERL, but with powerful typing and object oriented features. What is Python? Commonly used for producing HTML content on websites <type ‘object’> <class ‘A’> <class ‘B’> <class ‘C’> Useful built-in types (lists, dictionaries) Clean syntax, Powerful extensions Great for text Processing txt .pyc, .pyd, .pyo <html> <body> <Content> <Sidebar> <html> <body>
  6. 6. Slide 6 Why Python? Software Quality Developer Productivity Program Portability Support Libraries Component Integration Enjoyment » Python focuses on readability, coherence, and software quality in general which sets it apart from other languages in the scripting world.
  7. 7. Slide 7 Why Python? Software Quality Developer Productivity Program Portability Support Libraries Component Integration Enjoyment » Python code is typically one-third to one-fifth the size of equivalent C++ or Java code. That means there is less to type, less to debug, and less to maintain.
  8. 8. Slide 8 Why Python? Software Quality Developer Productivity Program Portability Support Libraries Component Integration Enjoyment » Python programs run unchanged on all major computer platforms. For Example- Windows, Linux, MAC OS etc.
  9. 9. Slide 9 Why Python? Software Quality Developer Productivity Program Portability Support Libraries Component Integration Enjoyment » Python comes with a large collection of prebuilt and portable functionality, known as the Standard Library. This library supports an array of application-level programming tasks, from text pattern matching to network scripting.
  10. 10. Slide 10 Why Python? Software Quality Developer Productivity Program Portability Support Libraries Component Integration Enjoyment » Python scripts can easily communicate with other parts of an application, using a variety of integration mechanisms.
  11. 11. Slide 11 Why Python? Software Quality Developer Productivity Program Portability Support Libraries Component Integration Enjoyment » Because of Python’s ease of use and built-in toolset, it makes the programming more pleasurable.
  12. 12. Slide 12 About Python Invented in the Netherlands in early 90s by Guido van Rossum. Named after “Monty Python”, a comedy group, as Python is fun to use. Open source and interpreted language. Considered a scripting language, but is much more than that. Scalable, object oriented and functional. Used by Google, increasingly popular. Python job trends from shows remarkable increase Python is at the top of the list among the top-dogs—Java, Javascript and PHP (according to Red Monk first quarter plot for 2014 ranking) Reference:  
  13. 13. Slide 13 Users of Python » Dropbox web-based file hosting service is implemented using Python » Both the Dropbox server (running in the cloud) and desktop client software are primarily written in Python. » Yahoo acquired Four11, whose address and mapping lookup services were implemented in Python. » Yahoo Maps uses Python. » Many components of the Google spider and search engine are written in Python. » Youtube is originally written in Python and mysql. Reference:
  14. 14. Slide 14 Users of Python » Zope Corporation has developed Blue Bream (a powerful Web application server) using Python that's available as free software. - » Ultraseek Server, a commercial search engine product, is implemented as an elaborate multi- threaded Python program. » The program contains over 11,000 lines of Python code, and the user interface is implemented with over 17,000 lines of Python-scripted HTML templates. » Shopzilla is a family of comparison shopping sites. » Shopzilla uses Python for configuration management and deployment, automated testing and internal tool development. » YUM, a package management utility for RPM- compatible Linux operating systems is written in Python. Reference:
  15. 15. Slide 15 Traditional Uses of Python Internet Scripting Cpython Interpreter Your C/C++ Program Embedded Scripting Database Programming Image Processing System Utilities GUIs(Tkinter, gtk, Windows) Artificial Intelligence
  16. 16. Slide 16 Uses of Python in Data Analytics New use-cases of python are the major growth driver for the increasing demand for python skills. These Use-cases are emerging because of various reasons. One of which is the new packages that were added into the standard library such as Pydoop, Pandas, Scipy etc. We will see how to use them in further sessions. Risk Management Analytics Weather Forecasting Ad Targeting Scientific Analysis
  17. 17. Slide 17 Python Users for Data Analytics Used for weather forecasting by AppNexus a real-time online-advertising-platform company uses the Python programming language to help conduct heavy-duty data analysis. The company is a leading provider of multi-manager/multi-asset risk management analytics. A complete Risk Management System is written in Python. Scientists in the Theoretical Physics Division at Los Alamos National Laboratory are using Python to control large-scale physics codes on massively parallel supercomputers, high-end servers, and clusters. Python plays a central role in controlling these simulations, performing data analysis, and visualization.
  18. 18. Slide 18 Python Timeline January 1994 October 16, 2000 December 3, 2008 Python 1.0 Python 2.0 Version 3.0 Python 1.5 - December 31, 1997 Python 1.6 - September 5, 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 2.5 - September 19, 2006 Python 2.6 - October 1, 2008 Python 2.7 - July 3, 2010 Python 3.1 - June 27, 2009 Python 3.2 - February 20, 2011 Python 3.3 - September 29, 2012 Python 3.4 - March 16, 2014
  19. 19. Slide 19 Which Version?  In this course we are going to use Python version 2.7.6 It is because:  The library support for version 3.x is not adequate to fulfill day to day business needs.  In the industry, most of the softwares are using version 2.x and hence it is the most widely used version. Python 2 or Python 3
  20. 20. Slide 20 YOU’RE FLYING! HOW?? PYTHON Language Features
  21. 21. Slide 21 Dynamic Interpreted Language Features YOU’RE FLYING! HOW?? PYTHON Highly Readable Object- oriented Interactive Functional
  22. 22. Slide 22 Installation: Python is pre-installed on most Unix systems, including Linux and MAC OS X. The pre-installed version is 2.x You can check the version installed on machine by executing the below command: python --version Please refer the detailed Installation Guide available in the LMS.(You will find the installation guides under Pythons Installation tab.) How to get Python? Note: We will be using Ubuntu virtual machine for practicals.
  23. 23. Slide 23 Getting Help in Python Python interpreter has a built-in function called help(‘Object’). This function is intended for interactive use which invokes the help system. To use this function, type- help() or help(‘Object’) To exit the help press ‘q’ For Example: Run help(‘for') - This displays the help for the for function. Run help() – This will open the help shell.  Type for “help” in Version 2.x & 3.x
  24. 24. Slide 24 Pydoc Pydoc is a documentation module for Python which gets installed with any Python distribution. Pydoc allows programmers to access Python's documentation, generate HTML pages with documentation specifics, and find the appropriate module for a particular job. Pydoc can be accessed from a module-specific GUI from within the Python Interpreter, or from a command line shell. Getting Help in Python(Contd.) “pydoc” (needs to be executed on Terminal)
  25. 25. Slide 25 Python IDE IDE is “Integrated Development Environment” which is used as the code editor, including a series of peripheral components and attachments. The most important feature of the Python IDE is beyond ordinary text editor, it offers a variety of language-specific shortcut editing functions which make it fast and comfortable for programmers while coding. The IDE that we will be using is Pycharm.
  26. 26. Slide 26 You can download Free Community Edition of Pycharm from the below link: Python IDE
  27. 27. Slide 27 To start Python, all you need to do is type python into your command line. Example: From here on, the $ sign denotes the start of a terminal command line, and the # sign denotes a comment. Python ignores anything written to the right of a # sign on a given line. $ python # Type python into your terminal's command line >>> # After a short message, the “>>>” symbol will appear. This signals the start of the Interpreter. Starting Python Starting “python” Interpreter
  28. 28. Slide 28 In addition to being a programming language, Python is also an interpreter. The interpreter reads other Python programs and commands, and executes them. Note that Python programs are compiled automatically before being scanned by the interpreter. The scanning process is hidden which makes Python faster than a pure interpreter. Once you're inside the Python interpreter, type in commands at will. Using the Interpreter
  29. 29. Slide 29 Comments: Any text to the right of the # symbol is mainly useful as notes for readers. Bulk Comments: Enclose the code in triple quoted strings (“””). Literal Constants: Any number or string that represents itself. Example: The number 2 always represents itself and nothing else - it is a constant because its value cannot be changed. Comments and Literals
  30. 30. Slide 30 Python supports several different numeric types: Integers Examples: 0, 1, 1234, -56 Integers are implemented as C longs Note: Dividing an integer by another integer will return only the integer part of the quotient, e.g. typing 7/2 will yield 3. Long integers Example: 999999999999999999999L Must end in either l or L Can be arbitrarily long Floating point numbers Examples: 0., 1.0, 1e10, 3.14e-2, 6.99E4 Implemented as C doubles Division works normally for floating point numbers: 7./2. = 3.5 Operations involving both floats and integers will yield floats: 6.4 – 2 = 4.4 Types of Numbers
  31. 31. Slide 31 Octal constants Examples: 0177, -01234 Must start with a leading 0 Hex constants Examples: 0x9ff, 0X7AE Must start with a leading 0x or 0X Complex numbers Examples: 3+4j, 3.0+4.0j, 2J Must end in j or J Typing in the imaginary part first will return the complex number in the order Re+ImJ Types of Numbers
  32. 32. Slide 32 Python Identifiers: Rules for Variable names A Python Identifier is a name used to identify a variable, function, class, module or other object. An identifier starts with a letter A to Z or a to z or an underscore (_) followed by zero or more letters, underscores and digits (0 to 9). Python is a case sensitive programming language. Python does not allow special characters such as @, $ and % within identifiers. Variables are used by just assigning them a value. No declaration or data type definition is needed/used. Identifier naming convention for Python Class names start with an uppercase letter and all other identifiers with a lowercase letter. Starting an identifier with a single leading underscore indicates by convention that the identifier is meant to be private. Starting an identifier with two leading underscores indicates a strongly private identifier. If the identifier also ends with two trailing underscores, the identifier is a language-defined special name. Identifier
  33. 33. Slide 33 Hello There!! My name is Annie. I love quizzes and puzzles and I am here to make you guys think and answer my questions. Annie’s Introduction
  34. 34. Slide 34 Annie’s Question 1. Which one of the below Identifiers is incorrect? A. _var B. __var C. $var D. var
  35. 35. Slide 35 Annie’s Answer $var is incorrect. It is because in python one cannot start the name of the identifier with special character.
  36. 36. Slide 36 Basic algebraic operations Four arithmetic operations: a+b, a-b, a*b, a/b Modulo : a%b Exponentiation: a**b Other elementary functions are not part of standard Python, but included in packages like NumPy and SciPy Comparison operators Greater than, less than, etc.: a < b, a > b, a <= b, a >= b Identity tests: a == b, a != b Operations on Numbers Arithmetic Division
  37. 37. Slide 37 Annie’s Question 2. When a = 5 and b = 2 then, what will be the value of (a*3*b) < (((a*b)-(b*b))/b)*(a*b) ? A. True B. False
  38. 38. Slide 38 Annie’s Answer The answer is False. It is because the value of left expression ( (a*3*b) ) and the right expression ( (((a*b)-(b*b))/b)*(a*b) ) are equal. (a*3*b) = (((a*b)-(b*b))/b)*(a*b) = 30
  39. 39. Slide 39 Bitwise operators Bitwise OR : a | b Bitwise and: a & b Bitwise exclusive or: a ^ b Operations on Numbers(Contd.) OR Operator AND Operator XOR Operator Shift a left or right by b bits: a << b, a >> b Left Shift Operator 5 places to the left Right Shift Operator
  40. 40. Slide 40 Annie’s Question 3. What is the output of ( 2 | 4 ), ( 2 & 4 ), and ( 2 ^ 4 ) respectively? A. 6, 0 and 6 B. 6, 6 and 6 C. 0, 6 and 6 D. 6, 0 and 0
  41. 41. Slide 41 Annie’s Answer The answer is 6, 0 and 6.
  42. 42. Slide 42 In Addition to other Operators: Not surprisingly, Python follows the basic PEMDAS (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction) order of operations. Python supports mixed-type math. The final answer will be of the most complicated type used. Operations on Numbers(Contd.)
  43. 43. Slide 43 Annie’s Question 4. What is the output of ( 100 * 20 ** 2 / 4 ) ? A. 1000000 B. 1 C. 10000 D. 100
  44. 44. Slide 44 Annie’s Answer The answer is 10000. According to PEMDAS, exponent will be calculated firstt, then multiplication will done and finally division. The expression ( 100 * 20 ** 2 / 4 ) is evaluated as: ( ( 100 * (20 ** 2) ) / 4 ) = (( 100 * 400 ) / 4) = ( 40000 / 4 ) = 10000
  45. 45. Slide 45 Python does not support a character type; these are treated as strings of length one, thus also considered a substring. Strings are immutable. Strings are ordered blocks of text Strings are enclosed in single or double quotation marks. Double quotation marks allow the user to extend strings over multiple lines without backslashes, which usually signal the continuation of an expression. Examples: 'abc', “ABC”. Concatenation and repetition Strings are concatenated with the + sign: >>> 'abc'+'def' 'abcdef' Strings are repeated with the * sign: >>> 'abc'*3 'abcabcabc’ Operations on Strings - I
  46. 46. Slide 46 Indexing and Slicing Operation Python starts indexing at 0. A string s will have indexes running from 0 to len(s)-1 (where len(s) is the length of s) in integer quantities. s[i] fetches the ith element in s. Example : Operations on Strings - II
  47. 47. Slide 47 Membership Checking In - Returns true if a character exists in the given string. not in - Returns true if a character does not exist in the given string. String Formatting Operator: % This operator is unique to strings and makes up for the pack of having functions from C's printf() family. Operations on Strings- III
  48. 48. Slide 48 capitalize(): Capitalizes first letter of string. count(str, beg= 0,end=len(string)): Counts how many times str occurs in string or in a substring of string if starting index beg and ending index end are given. encode(encoding='UTF-8',errors='strict'): Returns encoded string version of string; on error, default is to raise a ValueError unless errors is given with 'ignore' or 'replace‘. decode(encoding='UTF-8',errors='strict'): Decodes the string using the codec registered for Encoding. Encoding defaults to the default string encoding. index(str, beg=0, end=len(string)): Same as find(), but raises an exception if str not found. Built-in String Methods
  49. 49. Slide 49 max(str): Returns the max alphabetical character from the string str. min(str): Returns the min alphabetical character from the string str. replace(old, new [, max]): Replaces all occurrences of old in string with new or at most max occurrences if max given. upper(): Converts lowercase letters in string to uppercase. More String Methods
  50. 50. Slide 50 Indentation Leading whitespace (spaces and tabs) at the beginning of a logical line is used to compute the indentation level of the line, which in turn is used to determine the grouping of statements. Indentation is MUST in Python There are no braces to indicate blocks of code for class and function definitions or flow control. Blocks of code are denoted by line indentation, which is rigidly enforced. The number of spaces in the indentation is variable, but all statements within the block must be indented the same amount. Standard is to use 4 whitespaces as per official recommendation. Some editors automatically takes care of the indentation. Indentation
  51. 51. Slide 51 Python scripts are written in text files with the suffix “.py”. The scripts can be read by the interpreter in several ways: Running a Python Script Example: $ python # This will simply execute the script and return to the terminal afterwards Example Script “” Execution of “”
  52. 52. Slide 52 Assignment Write a program to print the: » Number of lowercase “a” and “o” in the following sentence. » Number of uppercase “L” and “N” in the following sentence. ‘Discover, Learning, with, Edureka’ Write a program to remove the following from: » Remove all w’s before and after .edureka. » Remove all lowercase letter before and after .edureka. » Remove all printable characters
  53. 53. Slide 53 Assignment Identify the type of numbers: » 0X7AE » 3+4j » -01234 » 3.14e-2 Write a program for String Formatting Operator % which should include the following conversions: » Character » Signed decimal integer » Octal integer » Hexadecimal integer (UPPERcase letters) » Floating point real number » Exponential notation (with lowercase 'e')
  54. 54. Slide 54 Pre-work Basic idea about different sequences: Getting to know file operations:
  55. 55. Slide 55 Further Reading A good set of information to begin with can be found at: » Official documentation page: »     For more on loops: »
  56. 56. Slide 56 What’s within the LMS Click here to expand and view all the elements of this Module
  57. 57. Slide 57 What’s within the LMS Pre-work Presentation Assignment Quiz Hands-on