Instant Hacking The Basics

							  Instant Hacking: The Basics




                                       Lotfi Ben Othmane
                                       Department of Computer Science
                                       Western Michigan University


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    Roadmap

           Installing Python
           Scripting with Python
           Python help
           Using Python language
           Getting input from a user
           Using modules
           Creating programs



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                                                                            1
Introduction

       Website: www.python.org
       We use Python 2.6 for Windows operating system
       (Windows XP, Windows Vista)
       Other operating systems that support Python
          Linux and Unix
          Macintosh
       Other implementations: IronPython (Windows),
       Jython (Java) , Django


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1. Installing Python

       Download msi installation for Python 2.6 from the
       link http://www.python.org/download/
       Run the downloaded msi file by double-clicking on it
       from windows explorer.
       Follow the instructions provided by the wizard until
       you finish the installation

       The installation program
       creates a shortcut on the
       computer desktop.

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                                                              2
1. Installing Python—Cont.




      Python
      IDLE




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2. Scripting with Python
           Generate an output

           Arithmetic operations


           Arithmetic operations
           with integers




            Arithmetic operations
            with decimals

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                                        3
3. Python Help




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4. Overview of the Basics of Python
Language

       Variables
       Statements
       Functions




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                                          4
    4.1. Variables

         A variable is a holder of a value. It has a name
         which is used to refer to its value. A variable name
         must start with a character (not a decimal)
         A variable could be assigned a value




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    4.1. Variables—Cont.


Not correct variable
name




Variable assignment




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                                                                     5
4.2 Statements

       It is a legitimate combinations of variables, reserved
       words, functions, and values that does something
       Examples
            Print x
            X=3




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4.3 Functions
    A little program you can use to perform a task
   Power function




Absolute value
function

 Round function

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                                                                 6
5. Getting Input from a User




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6. Using Modules
     Functions are organized in modules
     In Python you need to import a module or function
     before using it—Except built-in functions
     Import a module to the interpreter: import [module
     name]
     Call of a function within module: [module
     name].[function name]([parameters])




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                                                               7
     6. Using Modules—Cont.
Module import



Error function
call



Correct function
call




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     7. Using Programs

            So far we used the interactive interpreter: we write
            statements and get the results
            To write a program we need to create a script file.
            To do so, from Python IDLE, select File->New
            Windows, and write your code
            The extension for python script file is “py”
            You can save your script file (see next slides)
            A script module could be executed from the from
            the IDLE or using a windows command (see next
            slides)
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                                                                        8
7.1 Create a module




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7.2 Save a Module




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                           9
7.3 Run a module




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Conclusion

       The chapter covered
           Python installation
           Scripting
           Use of modules
           Creating programs




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