Python PPT1.pdf
- 1. INTRODUCTION TO PYTHON Dr. S. SELVAKANMANI, ASSOCIATE PROFESSOR, DEPARTMENT OF CSE, VELAMMAL I TECH
- 2. AGENDA Companies using Python Top languages for Data Science Introduction to Python & Features Installation of Python Working in IDLE Working in Jupyter Notebook Interactive Vs Script Mode
- 5. PYTHON - INTRODUCTION Developed in late 1980 by Guido Van Rossum at National Research Institute for Mathematics and Computer Science in Netherlands. Features of Python: Simple – It is simple to learn, read and write High level language – Program codes contains easy to read syntax that is later converted into a low level language (i.e binary codes)
- 6. PYTHON – INTRODUCTION Contd.. Open Source – It is freely available and the source code is available for free. Cross Platform/Portable - Python can run equally on different platforms such as Windows, Linux, Unix, and Macintosh etc. Interpreted Language – Python program written will be converted into intermediate language which is again translated into native or machine language for execution.
- 7. PYTHON – INTRODUCTION Contd..
- 8. PYTHON – INTRODUCTION Contd.. Interpreter translates just one statement of the program at a time into machine code. Vs Compiler scans the entire program and translates the whole of it into machine code at once.
- 9. PYTHON – INTRODUCTION Contd.. Case – Sensitive Language – Difference between Uppercase and lowercase letters. i.e area, Area. Object Oriented Language - Python structures a program by bundling related properties and behaviors into individual objects. Automatic Type Inference – Doesn‟t need to define the type of the data during its declaration.
- 10. PYTHON – INTRODUCTION Contd.. Scripting language – Uses an Interpreter to translate its source code. The interpreter reads and executes each line of code one at a time (like a “script” in a play/audition) No worry about memory allocation Interface with existing programming language – Comes with a large standard library that supports many common tasks. No Semicolon at the end of the statement
- 11. PYTHON – INSTALLATION Downloads available in www.python.org (Known as Cpython Installation and it comes with Python Interpreter , Python IDLE and PIP ( Package Installer ) Other Python distributions available in Anaconda Python distribution (https://www.anaconda.com/distribution/), comes with preloaded packages such as NumPy , SciPy, Pandas etc . Other Popular downloads available in form of Spyder IDE , PyCharm IDE etc.. (https://www.guru99.com/python-ide-code- editor.html)
- 12. PYTHON – WORKING IN IDLE IDLE – Integrated Development and Learning Environment Two modes of working : (i) Interactive mode and (ii) Script mode Interactive Mode : Writing & Executing one command at a time. ( Click Start – All Programs – Python x.x –IDLE ) Type the commands in the prompt (>>>) and hit Enter to see the output.
- 13. PYTHON – INTERACTIVE MODE >>> - Chevron
- 14. PYTHON – WORKING IN IDLE Script Mode : Writing & Executing Programs. (Click Start – All Programs – Python x.x – IDLE ) ( Click File – New – in Python IDLE shell ) Type the commands in the newly opened window and save the program with the extension (.py ) For Execution , Click Run – Run Module or Press F5.
- 15. PYTHON – SCRIPT MODE
- 16. PYTHON – FEATURES OF IDLE Multi-window text editor with syntax highlighting. Auto completion with smart indentation. Python shell to display output with syntax highlighting.
- 17. PYTHON – WORKING IN JUPYTER NOTEBOOK Launch Anaconda Navigator from Start – All Programs – Anaconda –Anaconda Navigator . Click on Launch JUPYTER Notebook (Opens in Web Browser) Select Python3 by clicking on the drop down arrow mark of New Option placed on the right hand side of the Dashboard. JUPYTER = JUlia, PYThon and R
- 18. PYTHON – JUPYTER NOTEBOOK
- 19. PYTHON – WORKING IN JUPYTER NOTEBOOK In this window, the code can be written within the cell provided. If using Interactive mode, Type the commands in the Cell and Press Run or Shift Enter. If using Script mode, Type the commands in the Cell , save the file by clicking on Untitled1 , Click Run to run your program
- 20. PYTHON – JUPYTER NOTEBOOK
- 21. PYTHON – INTERACTIVE Vs SCRIPT MODE
- 22. PYTHON – VIRTUAL ENVIRONMENT https://repl.it colab.research.google.com https://www.codechef.com/ide https://pynative.com/online-python-code- editor-to-execute-python-code/ https://www.jdoodle.com/python3- programming-online/
- 23. PYTHON – SYNTAX Keywords – Set of predefined words. A prescribed rule of usage for each keyword is called a syntax. Python 3.x interpreter has 33 keywords defined in it. Since they have a predefined meaning attached, they cannot be used for any other purpose. To know the list of python keywords: >>>help('keywords')
- 24. PYTHON – LIST OF KEYWORDS : 33 nos.
- 25. PYTHON – SYNTAX Apart from Keywords, Python program can have variables, functions, classes, modules, packages etc. Identifier is the name given to these programming elements. An identifier should start with either an alphabet letter (lower or upper case) or an underscore (_). After that, more than one alphabet letters (a-z or A-Z), digits (0- 9) or underscores may be used to form an identifier. No other characters are allowed such as @,#,$, etc Identifiers are case – sensitive.
- 26. PYTHON – SYNTAX Eg: Names like myClass, var_1, and this_is_a_long_variable
- 27. PYTHON – STATEMENT By default, the Python interpreter treats a piece of text terminated by hard carriage return (i.e new line character) as one statement. It means each line in a Python script is a statement. (Just as in C/C++/C#, a semicolon ; denotes the end of a statement). Eg1: msg="Hello World" Eg2: code=123 Eg3: name="Steve" Use the semicolon ; to write multiple statements in a single line. Eg: msg='"Hello World";code=123;name="Steve"'
- 28. PYTHON – STATEMENT Continuation of Statement: We can show the text spread over more than one lines to be a single statement by using the backslash () as a continuation character. Eg: msg="Hello Python Learners <enter> Welcome to Python Tutorial <enter> from CSE Department"
- 29. PYTHON – INDENTS Many times it is required to construct a block of more than one statements. For example there might be multiple statements that are part of the definition of a function or method. Most of the programming languages like C, C++, Java use braces { } to define a block of code. But, python uses indentation. Blocks of code are denoted by line indentation. It is a space given to the block of codes for class and function definitions or flow control.
- 30. PYTHON – INDENTS When a block is to be started, type the colon symbol (:) and press Enter. Any Python-aware editor (like IDLE) goes to the next line leaving an additional whitespace (called indent). Subsequent statements in the block follow the same level of indent.
- 31. PYTHON – COMMENTS A hash sign (#) is the beginning of a comment. Anything written after # in a line is ignored by interpreter. Eg: percentage = (minute * 100) / 60 # calculating percentage of an hour Python does not have multiple-line commenting feature. You have to comment each line individually as follows : # this is a comment print ("Hello World") print ("Welcome to Python Tutorial") #this is also a comment but after a statement Use triple – quote for mutli – line comment
- 32. PYTHON – INPUT AND OUTPUT Input is data entered by user (end user) in the program. In python, input () function is available for input. Syntax is: variable = input (“data”) Eg: >>> x=input("enter the name:") enter the name: George >>>y=int(input("enter the number")) enter the number 3 Python accepts string as default data type. Conversion is required for type. A function is a block of code which only runs when it is called. A set of statements which perform a specific tasks.
- 33. PYTHON – INPUT AND OUTPUT OUTPUT: Output can be displayed to the user using print statement . Syntax: print (expression/constant/variable) Example: >>> print ("Hello") Hello
- 34. PYTHON – VARIABLE Any value of certain type is stored in the computer's memory for processing. Out of available memory locations, one is randomly allocated for storage. In order to conveniently and repeatedly refer to the stored value, it is given a suitable name. A value is bound to a name by the assignment operator '='. Eg: A = 3
- 35. PYTHON – VARIABLE Eg: A = 3 A is the identifier and 3 is the value assigned to it. The same identifier can be used to refer to another value. Eg: A = „hello‟ So, the value being referred can change (or vary), hence it is called a variable. It is important to remember that a variable is a name given to a value, and not to a memory location storing the value.
- 36. THANK YOU