book

Introducing Python, 3rd Edition

by Bill Lubanovic

September 2025

Beginner to intermediate

660 pages

12h 48m

English

O'Reilly Media, Inc.

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Includes Quizzes

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AudienceChanges in the Third EditionOutlinePython VersionsAbout the AuthorConventions Used in This BookUsing Code ExamplesO’Reilly Online LearningHow to Contact UsAcknowledgments
MysteriesLittle Python ProgramsSetupInstall PythonUpgrade PythonRun Python ProgramsThe Python Interactive InterpreterPython FilesBuilt-In Python FeaturesThe Python Standard LibraryThird-Party Python PackagesA Bigger ExampleReview/Preview
A ComputerBits and BytesMultibyte TypesVariablesAssign a Value to a VariableChange the Value of a VariableDelete a VariableName VariablesFollow Naming ConventionsPython TypesSpecify ValuesObjects as Plastic Boxes in MemoryReview/PreviewPractice
BooleansIntegersLiteral IntegersInteger OperationsIntegers and VariablesPrecedenceBasesType ConversionsHow Big Is an int?FloatsFloats Are Not ExactFractionsDecimalsMath FunctionsReview/PreviewPractice
Create with QuotesCreate with str()Escape with \Combine with +Duplicate with *Get a Character by [ offset ]Get a Substring with a SliceGet Length with len()Split with split()Combine with join()Substitute with replace()Work with Prefixes and SuffixesStrip with strip()Search and SelectChange CaseSet AlignmentApply FormattingOld style: %New style: {} and format()Newest Style: f-stringsReview/PreviewPractice
BytesCreate with QuotesCreate with bytes()Create from a Hex StringDecode and Encode Bytes and StringsConvert to a Hex StringGet One Byte by [ offset ]Get a SliceCombine with +Repeat with *BytearrayCreate with bytearray()Get One Byte by [ offset ]Get Multiple Bytes with a SliceModify One Byte by [ offset ]Modify Multiple Bytes with replace()Modify Multiple Bytes with a SliceInsert a Byte with insert()Append One Byte with append()Append Multiple Bytes with extend()Combine with +Repeat with *Review/PreviewPractice
Comment with #Continue Lines with \Compare with if, elif, and elseWhat Is True?Do Multiple Comparisons with inNew: I Am the WalrusMatchSimple MatchesStructural MatchesReview/PreviewPractice
Repeat with whileCancel with breakSkip Ahead with continueCheck break Use with elseIterate with for and inCancel with breakSkip with continueCheck break Use with elseGenerate Number Sequences with range()Review/PreviewPractice
TuplesCreate with Commas and ()Create with tuple()Get an Item by [ offset ]Combine with +Duplicate with *CompareIterate with for and inModify?ListsCreate with []Create or Convert with list()Create from a String with split()Get an Item by [ offset ]Get Items with a SliceAdd an Item to the End with append()Add an Item by Offset with insert()Duplicate with *Combine with extend() or +Change an Item with [ offset ]Change Items with a SliceDelete an Item by Offset with delDelete an Item by Value with remove()Get an Item by Offset and Delete It with pop()Delete All Items with clear()Find an Item’s Offset by Value with index()Test for a Value with inCount Occurrences of a Value with count()Convert a List to a String with join()Reorder Items with sort() or sorted()Get Length with len()Assign with =Copy with copy(), list(), or a SliceCopy Everything with deepcopy()Compare ListsIterate with for and inIterate Multiple Sequences with zip()Iterate Multiple Sequences with zip_longest()Create a List with a ComprehensionCreate Lists of ListsTuples Versus ListsThere Are No Tuple ComprehensionsReview/PreviewPractice

DictionariesCreate with {}Create with dict()Convert with dict()Add or Change an Item by [ key ]Get an Item by [ key ] or with get()Iterate with for and inGet Length with len()Combine/update dictsDelete an Item by Key with delGet an Item by Key and Delete It with pop( key )Delete All Items with clear()Test for a Key with inAssign with =Copy with copy()Copy Everything with deepcopy()Compare DictionariesUse Dictionary ComprehensionsSetsCreate with set() or {}Get Length with len()Add an Item with add()Delete an Item with remove()Combine with |Iterate with for and inTest for a Value with inUse Combinations and OperatorsCreate Set ComprehensionsCreate an Immutable Set with frozenset()Review/PreviewPractice
Define a Function with defCall a Function with ParenthesesArguments and ParametersNone, Truthiness, and FalsinessPositional ArgumentsKeyword ArgumentsDefault Parameter ValuesPack/Unpack Positional Arguments with *Pack/Unpack Keyword Arguments with **Keyword-Only (*) and Position-Only (/) ArgumentsMutable and Immutable ArgumentsDocstringsFunctions Are First-Class CitizensFunction Arguments Are Not a TupleInner FunctionsClosuresAnonymous Functions: LambdaGeneratorsGenerator FunctionsGenerator ComprehensionsDecoratorsNamespaces and ScopeDunder NamesRecursionAsync Functions, BrieflyExceptionsHandle Errors with try and exceptUse FinallyMake Your Own ExceptionsReview/PreviewPractice
What Are Objects?Simple ObjectsDefine a Class with classAssign AttributesMethodsInitializationInheritanceInherit from a Parent ClassOverride a MethodAdd a MethodGet Help from Your Parent with super()Use Multiple InheritanceInclude MixinsIn self DefenseAttribute AccessDirect AccessGetters and SettersProperties for Attribute AccessProperties for Computed ValuesName Mangling for PrivacyClass and Object AttributesMethod TypesInstance MethodsClass MethodsStatic MethodsDuck TypingMagic MethodsAggregation and CompositionWhen to Use Objects or Something ElseNamed TuplesDataclassesAttrsReview/PreviewPractice
Modules and the import StatementImport a ModuleImport a Module with Another NameImport Only What You Want from a ModulePackagesThe Module Search PathRelative and Absolute ImportsNamespace PackagesModules Versus ObjectsGoodies in the Python Standard LibraryHandle Missing Keys with setdefault() and defaultdict()Count Items with Counter()Order by Key with OrderedDict()Stack + Queue == dequeIterate over Code Structures with itertoolsGet RandomMore Batteries: Get Other Python CodeReview/PreviewPractice
Find Python CodeInstall PackagesUse PipInstall with a Native Package ManagerInstall from SourceVirtual EnvironmentsVirtualenv and VenvPipenvPoetryCondauvIntegrated Development EnvironmentsIPythonJupyter NotebookJupyterLabSource ControlMercurialGitReview/PreviewPractice
Type HintsVariable HintsFunction HintsMypyDocumentationCommentsDocstringsMarkup Text FilesReview/PreviewPractice
PylintRuffUnittestDoctestPytestExamplesFixturesParametrizationHypothesisNoxContinuous IntegrationReview/PreviewPractice
AssertPrintF-stringsPprint()IceCreamDecoratorsLoggingPdbBreakpoint()Review/PreviewPractice
Text Strings: UnicodePython Unicode StringsUTF-8EncodeDecodeHTML EntitiesNormalizationText Strings: Regular ExpressionsFind Exact Beginning Match with match()Find First Match with search()Find All Matches with findall()Split at Matches with split()Replace at Matches with sub()PatternsUsing Special CharactersUsing SpecifiersSpecifying match() OutputReview/PreviewPractice
Convert Binary Data with structExtraction with Binary Data ToolsConvert Bytes/Strings with binascii()Use Bit OperatorsReview/PreviewPractice
Leap YearThe datetime ModuleThe time ModuleRead and Write Dates and TimesAll the ConversionsAlternative ModulesReview/PreviewPractice
File Input and OutputCreate or Open with open()Write a Text File with print()Write a Text File with write()Read a Text File with read(), readline(), or readlines()Write a Binary File with write()Read a Binary File with read()Close Files Automatically by Using withChange Position with seek()Memory MappingFile OperationsCheck Existence with exists()Check Type with isfile()Copy with copy()Change Name with rename()Link with link() or symlink()Change Permissions with chmod()Change Ownership with chown()Delete a File with remove()Directory OperationsCreate with mkdir()Delete with rmdir()List Contents with listdir()Change Current Directory with chdir()List Matching Files with glob()PathnamesGet a Pathname with abspath()Get a symlink Pathname with realpath()Build a Pathname with os.path.join()Use pathlibBytesIO and StringIOFile Formats: DeterminationReview/PreviewPractice
Programs and ProcessesCreate a Process with subprocessCreate a Process with multiprocessingKill a Process with terminate()Get System Info with osGet Process Info with psutilCommand AutomationInvokeOther Command HelpersConcurrencyQueuesProcessesThreadsThe GILConcurrent.futuresGreen Threads and geventTwistedasyncioCoroutines and Event LoopsAsyncio AlternativesAsync Versus…Async Frameworks and ServersRedisBeyond QueuesReview/PreviewPractice
TCP/IPSocketsScapyNetcatNetworking PatternsThe Request-Reply PatternRequest-Reply: ZeroMQRequest-Reply: Other Messaging ToolsThe Publish-Subscribe PatternPub-Sub: RedisPub-Sub: ZeroMQPub-Sub: Other ToolsInternet ServicesDomain Name SystemPython Email ModulesOther ProtocolsWeb Services and APIsData SerializationSerialize with pickleUse Other Serialization FormatsRemote Procedure CallsXML-RPCJSON RPCMessagePack RPCzerorpcgRPCRemote ManagementBig Fat DataHadoopSparkDiscoDaskCloudsAmazon Web ServicesGoogle CloudMicrosoft AzureOpenStackDockerKubernetesReview/PreviewPractice
Text FilesTabular and Delimited Text FilesCSVXMLAn XML Security NoteHTMLJSONYAMLTOMLTablibConfiguration FilesBinary FilesPadded Binary Files and Memory MappingSpreadsheetsHDF5TileDBRelational DatabasesSQLDB-APISQLiteDuckDBMySQLPostgreSQLSQLAlchemyOther Database Access PackagesNoSQL Data StoresThe dbm FamilyMemcachedRedisRedis Alternative: Valkey?Document DatabasesTime-Series DatabasesGraph DatabasesOther NoSQLFull-Text DatabasesVector DatabasesGeospatial DatabasesReview/PreviewPractice
Web BasicsHTTP TestingTelnetcurlHTTPiehttpbinWeb ClientsThe Standard LibraryRequestsOther Web ClientsWeb ServersThe Simplest Python Web ServerWeb Server Gateway InterfaceASGIApacheNGINXOther Python Web ServersWeb Server FrameworksBottleFlaskDjangoFastAPILitestarDatabase FrameworksWeb Services and AutomationwebbrowserwebviewWeb APIs and RESTWebSocketsWebhooksWeb FrontendshtmxFastHTMLCrawl and ScrapeScrapyBeautiful SoupRequests-HTMLLet’s Watch a MovieReview/PreviewPractice
Standard PythonFormat ConversionsMathComplex NumbersCalculate Accurate Floating Point Values with decimalPerform Rational Arithmetic with fractionsUse Packed Sequences with arrayStatisticsMatrix MultiplicationNumPyMake an Array with array()Make an Array with arange()Make an Array with zeros(), ones(), or random()Change an Array’s Shape with reshape()Get an Element with []Array MathLinear AlgebraSciPypandasPolarsDuckDBData VisualizationReview/PreviewPractice
It Turns Out…Expert SystemsPerceptronsThe BreakthroughImage Recognition: ImageNet and AlexNetLarge Language ModelsThe ChatGPT MomentRetrieval Augmented GenerationAgentsEfficiencyCreate Models: Python FrameworksCurrent ModelsA Million Models: Hugging FaceWorking Examples With OllamaInstall OllamaChoose a ModelChoose Another ModelOllama ReferencesReferencesReview/PreviewPractice
Computer HardwareMeasure TimingProfileAlgorithms and Data StructuresArrays Versus Lists and TuplesCacheCythonNumPy and SciPyC or Rust ExtensionsTaichiPyPyNumbaStandard Python JITMojoBackgroundDesignExamplesLimitationsConclusionReview/PreviewPractice
2. Types and Variables3. Numbers4. Strings5. Bytes and Bytearray6. If and Match7. For and While8. Tuples and Lists9. Dictionaries and Sets10. Functions11. Objects12. Modules and Packages13. Development Environment14. Type Hints and Documentation15. Testing16. Debugging17. Text Data18. Binary Data19. Dates and Times20. Files21. Data in Time: Concurrency22. Data in Space: Networks23. Data in a Box: Persistent Storage24. The Web25. Data Science26. AI27. Performance

Overview

Stuck in a coding conundrum? Whether you're an advanced beginner, an intermediate developer, or a curious newcomer, the complexities of coding can often feel like a labyrinth with no exit. With Python, however, you can start writing real code quickly—but where should you start?

In this updated third edition, Bill Lubanovic acts as your personal guide to Python, offering a clear path through the intricacies and capabilities of this much-beloved coding language, including new chapters on AI models and performance enhancements. Easy to understand and enjoyable to read, this book not only teaches you the core concepts but also dives into practical applications that bridge the gap between learning and doing. By reading it, you will:

Understand everything from basic data structures to advanced features
Gain insights into using Python for files, networking, databases, and data science
Learn testing, debugging, code reuse, and other essential development tips
Explore how Python can be utilized in business, science, and the arts