book

Python Without Fear

Name: Python Without Fear
Author: Brian Overland
ISBN: 9780134688251

by Brian Overland

October 2017

Beginner to intermediate

464 pages

12h 35m

English

Addison-Wesley Professional

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Includes

Sandbox

Cover Page
Title Page
Copyright Page
Dedication Page
Contents
Preface
Steering Around the “Gotchas”How to Think “Pythonically”Intermediate and Advanced FeaturesLearning in Many Different StylesWhat’s Going on “Under the Hood”Why Python?
Acknowledgments
Author Bio
Chapter 1 Meet the Python
A Brief History of PythonHow Python Is DifferentHow This Book WorksInstalling PythonBegin Using Python with IDLECorrecting Mistakes from Within IDLEDealing with Ends of LinesAdditional Help: Online Sources
Chapter 2 A Python Safari: Numbers
Python and NumbersInterlude Why Doesn’t C++ Support Infinite Integers?Interlude How Big Is a Google?Python and Floating-Point NumbersAssigning Numbers to VariablesInterlude What Do Python Assignments Really Do?Variable-Naming Conventions in This BookSome Python ShortcutsChapter 2 Summary

Chapter 3 Your First Programs
Temperatures Rising?Interlude Python’s Use of IndentationPutting in a Print MessageSyntax SummariesExample 3.1. Quadratic Equation as a FunctionHow It WorksGetting String InputGetting Numeric InputExample 3.2. Quadratic Formula with I/OHow It WorksFormatted Output StringExample 3.3. Distance Formula in a ScriptHow It WorksChapter 3 Summary
Chapter 4 Decisions and Looping
Decisions Inside a Computer ProgramConditional and Boolean OperatorsThe if, elif, and else KeywordsInterlude Programs and Robots in WestworldExample 4.1. Enter Your AgeHow It Workswhile: Looping the LoopExample 4.2. FactorialsHow It WorksOptimizing the CodeExample 4.3. Printing Fibonacci NumbersHow It Works“Give Me a break” StatementExample 4.4. A Number-Guessing GameHow It WorksInterlude Binary Searches and “O” ComplexityChapter 4 Summary
Chapter 5 Python Lists
The Python Way: The World Is Made of CollectionsProcessing Lists with forModifying Elements with for (You Can’t!)Example 5.1. A Sorting ApplicationHow It WorksOptimizing the CodeIndexing and SlicingCopying Data to SlicesRangesExample 5.2. Revised Factorial ProgramHow It WorksOptimizing the CodeExample 5.3. Sieve of EratosthenesHow It WorksOptimizing the CodeList Functions and the in KeywordInterlude Who Was Eratosthenes?Chapter 5 Summary
Chapter 6 List Comprehension and Enumeration
Indexes and the enumerate FunctionThe Format String Method RevisitedExample 6.1. Printing a TableHow It WorksSimple List ComprehensionExample 6.2. Difference Between SquaresHow It WorksInterlude Proving the Equation“Two-Dimensional” List ComprehensionList Comprehension with ConditionalExample 6.3. Sieve of Eratosthenes 2How It WorksOptimizing the Code: SetsExample 6.4. Pythagorean TriplesHow It WorksInterlude The Importance of PythagorasChapter 6 Summary
Chapter 7 Python Strings
Creating a String with Quote MarksIndexing and “Slicing”String/Number ConversionsExample 7.1. Count Trailing ZerosHow It WorksInterlude Python Characters vs. Python StringsStripping for Fun and ProfitExample 7.2. Count Zeros, Version 2How It WorksLet’s Split: The split MethodBuilding Strings with Concatenation (+)Example 7.3. Sort Words on a LineHow It WorksThe join MethodChapter 7 Summary
Chapter 8 Single-Character Ops
Naming Conventions in This ChapterAccessing Individual Characters (A Review)Getting Help with String MethodsTesting Uppercase vs. LowercaseConverting Case of LettersTesting for PalindromesExample 8.1. Convert Strings to All CapsHow It WorksOptimizing the CodeExample 8.2. Completing the Palindrome TestHow It WorksOptimizing the CodeInterlude Famous PalindromesConverting to ASCII CodeConverting ASCII to CharacterExample 8.3. Encode StringsHow It WorksInterlude The Art of CryptographyExample 8.4. Decode StringsHow It WorksChapter 8 Summary
Chapter 9 Advanced Function Techniques
Multiple ArgumentsReturning More Than One ValueInterlude Passing and Modifying ListsExample 9.1. Difference and Sum of Two PointsHow It WorksArguments by NameDefault ArgumentsExample 9.2. Adding MachineHow It WorksOptimizing the CodeImporting Functions from ModulesExample 9.3. Dice Game (Craps)How It WorksInterlude Casino Odds MakingChapter 9 Summary
Chapter 10 Local and Global Variables
Local Variables, What Are They Good For?Locals vs. GlobalsIntroducing the global KeywordThe Python “Local Variable Trap”Interlude Does C++ Have Easier Scope Rules?Example 10.1. Beatles Personality Profile (BPP)How It WorksExample 10.2. Roman NumeralsHow It WorksOptimizing the CodeInterlude What’s Up with Roman Numerals?Example 10.3. Decode Roman NumeralsHow It WorksOptimizing the CodeChapter 10 Summary
Chapter 11 File Ops
Text Files vs. Binary FilesThe Op System (os) ModuleInterlude Running on Other SystemsOpen a FileLet’s Write a Text FileExample 11.1. Write File with PromptHow It WorksRead a Text FileFiles and Exception HandlingInterlude Advantages of try/exceptExample 11.2. Text Read with Line NumbersHow It WorksOther File ModesChapter 11 Summary
Chapter 12 Dictionaries and Sets
Why Do We Need Dictionaries, Ms. Librarian?Adding and Changing Key-Value PairsAccessing ValuesSearching for KeysInterlude What Explains Dictionary “Magic”?Example 12.1. Personal Phone BookHow It WorksConverting Dictionaries to ListsExample 12.2. Reading Items by PrefixHow It WorksExample 12.3. Loading and Saving to a FileHow It WorksAll About SetsOperations on SetsInterlude What’s So Important About Sets?Example 12.4. Revised Sieve of EratosthenesHow It WorksChapter 12 Summary
Chapter 13 Matrixes: 2-D Lists
Simple MatrixesAccessing ElementsIrregular Matrixes and Length of a RowMultiplication (*) and ListsThe Python Matrix ProblemHow to Create N*M Matrixes: The SolutionInterlude Why Isn’t It Easier?Example 13.1. Multiplication TableHow It WorksExample 13.2. User-Initialized MatrixHow It WorksOptimizing the CodeHow to Rotate a MatrixInterlude Pros and Cons of Garbage CollectionExample 13.3. Complete Rotation ExampleHow It WorksOptimizing the CodeChapter 13 Summary
Chapter 14 Winning at Tic-Tac-Toe
Design of a Tic-Tac-Toe BoardPlan of This ChapterPhase 1Phase 2Phase 3Python One-Line if/elseExample 14.1. Simple Two-Player GameHow It WorksInterlude Variations on Tic-Tac-ToeThe count Method for ListsExample 14.2. Two-Player Game with Win DetectionHow It WorksIntroducing the Computer PlayerExample 14.3. Computer Play: The Computer Goes FirstHow It WorksPlaying SecondInterlude The Art of HeuristicsChapter 14 Summary
Chapter 15 Classes and Objects I
What’s an Object?Classes in PythonHow Do I Define a Simple Class?How Do I Use a Class to Create Objects?How Do I Attach Data to Objects?How Do I Write Methods?The All-Important __init__ MethodInterlude Why This self Obsession?Design for a Database ClassInterlude C++ Classes Compared to PythonExample 15.1. Tracking EmployeesHow It WorksDefining Other MethodsDesign for a Point3D ClassPoint3D Class and Default ArgumentsThree-Dimensional Tic-Tac-ToeExample 15.2. Looking for a 3-D WinHow It WorksExample 15.3. Calculating Ways of WinningHow It WorksOptimizing the CodeChapter 15 Summary
Chapter 16 Classes and Objects II
Getting Help from Doc StringsFunction Typing and “Overloading”Interlude What Is Duck Typing?Variable-Length Argument ListsExample 16.1. PointN ClassHow It WorksOptimizing the CodeInheritanceThe Fraction ClassExample 16.2. Extending the Fraction ClassHow It WorksClass Variables and MethodsInstance Variables as “Default” ValuesExample 16.3. Polygon “Automated” ClassHow It WorksInterlude OOPS, What Is It Good For?Chapter 16 Summary
Chapter 17 Conway’s Game of Life
Interlude The Impact of “Life”Game of Life: The Rules of the GameGenerating the Neighbor CountDesign of the ProgramExample 17.1. The Customized Matrix ClassHow It WorksMoving the Matrix Class to a ModuleExample 17.2. Printing a Life MatrixHow It WorksThe Famous Slider PatternExample 17.3. The Whole Game of Life ProgramHow It WorksInterlude Does “Life” Create Life?Chapter 17 Summary
Chapter 18 Advanced Pythonic Techniques
GeneratorsExploiting the Power of GeneratorsExample 18.1. A Custom Random-Number GeneratorHow It WorksInterlude How Random Is “Random”?PropertiesGetter MethodsSetter MethodsPutting Getters and Setters TogetherExample 18.2. Multilevel Temperature ObjectHow It WorksDecorators: Functions Enclosing Other FunctionsPython DecorationExample 18.3. Decorators as Debugging ToolsHow It WorksChapter 18 Summary
Chapter 19 Tkinter and Graphical Programming
Begin Using tkinterDisplay “Hello, World!”“Hello, World” with a ButtonChanging Attributes During ExecutionExample 19.1. The Swami KnowsHow It WorksGetting AttributesIntroducing the Canvas WidgetBinding Canvas EventsEvent HandlersMore About the “pack“ Geometry ManagerExample 19.2. Color ChangerHow It WorksThe “grid“ Geometry ManagerTic-Tac-Toe with Canvas WidgetsSubclassing the Canvas ClassExample 19.3. GUI Tic-Tac-ToeHow It WorksWhere to Go from HereChapter 19 Summary
Appendix A Python Operator Precedence Table
Appendix B Summary of Most Important Formatting Rules for Python 3.0
1. Formatting Ordinary Text2. Formatting Arguments3. Specifying Order of Arguments4. Right Justification Within Field of Size N5. Left Justification Within Field of Size N6. Truncation: Limit Size of Print Field7. Combined Truncation and Justification8. Length and Precision of Floating-Point Numbers9. The Padding Character
Appendix C Glossary
Index

Content preview from Python Without Fear

10. Local and Global Variables

One of the issues in programming is communication—how do you share information between two functions or between a group of functions? The most direct way is to use global variables.

But Python has idiosyncratic rules about global and local variables. Python likes to do things its own way.

This chapter covers

The difference between local and global variables

The global keyword

Using this keyword to prevent “the local ...

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Python Without Fear

by Brian Overland

10. Local and Global Variables

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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