introduction to python unit notes .pdf

notes for python programming. for beginners

1. BCA
IN24C04
BATCH 2024
(Semester 2)
73 Hrs

2. BCA
A.MarkLutzLearningpython(UnitI-III)O’Reilly
Publication2013,5thEdition.
B.AllenB.Downey ThinkPython:HowtoThink
likeaComputerScientist(UnitIV-V)O’Reilly
Publishers,2016,2ndEdition.
C.KapilKapoorIndianKnowledgesystemsIndian
InstituteofAdvancedstudy 2005,1stEdition.
CA: 25
ESE: 75
TOTAL: 100
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3. BCA
Course Code : IN24C04
Credits : 3
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A.E.Balagurusamy ProblemSolvingandPython
ProgrammingMcGraw-Hill2017,1stEdition.
B.GuidovanRossumandFredL.DrakeJr AnIntroduction
toPython–RevisedandupdatedforPython3.2 Python
SoftwareFoundation,NetworkTheoryLtd2011, 1st
Edition.
C.WesleyJChunCorePythonApplicationsProgramming
PrenticeHall2012,3rdEdition.

4. BCA
SYLLABUS FOR UNIT 1 [10 Hrs]
Introduction:Whydopeopleusepython-
Pythonascriptinglanguage-UsersofPython-
NeedofPython-Python’sTechnicalStrengths-
HowPythonrunsprograms:Introducingthe
PythonInterpreter-ProgramExecution-
Execution Model Variation: Python
ImplementationAlternatives.
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5
INTRODUCTION
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•Pythonisahigh-level,interpreted,general-
purpose,dynamicprogramminglanguage.
•Pythonwasconceivedinthelate1980sand
itsusagebeganfromDecember1989.
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7. BCA
•Itisawidelyusedprogramminglanguage.
•Pythonpossessesapropertyofcodetermed
reusability.
•Thesyntaxofpythonprogramscanexpress
conceptsinfewerlinesascomparedtoprogramsin
C,C++andJAVA.
•Pythoncanbeusedinmultipleprogrammingstyles,
includingobject-oriented,functionalprogramming,
proceduralprogrammingandimperativestyles.
•Pythonsupportsautomaticmemorymanagement.
•Pythonisfreeandopen-sourcesoftware.
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8. BCA
•ItwasinitiallydesignedbyGuidovanRossum
in1991anddevelopedbyPythonSoftware
Foundation.
•Pythonisaprogramminglanguagethatlets
youworkquicklyandintegratesystemsmore
efficiently.
•TherearetwomajorPythonversions-Python
2andPython3.Botharequitedifferent.
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9. BCA
WhatisPython?
•Pythonisapopularprogramminglanguage.It
wascreatedbyGuidovanRossum,and
releasedin1991.
•Itisusedfor:
–webdevelopment(server-side),
–softwaredevelopment,
–mathematics,
–systemscripting.
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10. BCA
WhatcanPythondo?
Itcanbeusedonaservertocreateweb
applications.
Itcanbeusedalongsidesoftwaretocreate
workflows.
Itcanconnecttodatabasesystems.
Itcanalsoreadandmodifyfiles.
Itcanbeusedtohandlebigdataandperform
complexmathematics.
Itcanbeusedforrapidprototyping,orfor
production-readysoftwaredevelopment.
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11. BCA
WhyPython?
Pythonworksondifferentplatforms(Windows,
Mac,Linux,RaspberryPi,etc).
PythonhasasimplesyntaxsimilartotheEnglish
language.
Pythonhassyntaxthatallowsdeveloperstowrite
programswithfewerlinesthansomeother
programminglanguages.
Pythonrunsonaninterpretersystem,meaning
thatcodecanbeexecutedassoonasitiswritten.
Thismeansthatprototypingcanbeveryquick.
Pythoncanbetreatedinaproceduralway,an
object-orientatedwayorafunctionalway.
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Whydopeopleusepython?
PeopleusePythonforawiderangeof
applicationsduetoitsversatility,easeofuse,and
vastecosystem.
Python’sversatility,simplicity,andvast
ecosystemmakeitanidealchoiceforbeginners,
professionals,andcompaniesalike.
Whetherit'sbuildingawebapp,analyzingdata,
ordevelopingmachinelearningmodels,Python
offersastraightforwardandpowerfulsolution.
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EasytoLearnandUse:
PythonhasasimplesyntaxthatresemblesEnglish,
makingitbeginner-friendly.
Minimaluseofcomplexconstructsallowsforfaster
learningandimplementation.
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print("Hello, World!")

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Versatility:
Pythoncanbeusedforvariouspurposes,including:
WebDevelopment:FrameworkslikeDjango,Flask.
DataScienceandMachineLearning:Librarieslike
Pandas,NumPy,TensorFlow.
Automation:Scriptingrepetitivetasks.
GameDevelopment:LibrarieslikePygame.
EmbeddedSystems:Usedinmicrocontrollers(e.g.,
RaspberryPi).
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ExtensiveLibrariesandFrameworks:
Pythonhasarichcollectionofpre-builtlibrariesfor
virtuallyanydomain.
Examples:
DataAnalysis:Pandas,NumPy.
MachineLearning:TensorFlow,Scikit-learn.
WebScraping:BeautifulSoup,Scrapy.
Visualization:Matplotlib,Seaborn.
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Cross-PlatformCompatibility:
Pythonrunsonvariousplatforms,includingWindows,
macOS,andLinux.
Writecodeonceandrunitanywherewithoutsignificant
modifications.
StrongCommunitySupport:
Avastandactivecommunityprovidesextensive
resources,tutorials,andsupport.
Availabilityofopen-sourcecontributionsandforumslike
StackOverflow.
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ProductivityandEfficiency:
Python’ssimplicityanddynamictypingmake
developmentfastercomparedtomanyother
programminglanguages.
Highproductivitymakesitsuitableforrapidprototyping.
ApplicationsinEmergingTechnologies:
DataScienceandAI:Pythonisthego-tolanguagefor
analyzingdata,buildingpredictivemodels,andtrainingAI
systems.
IoT(InternetofThings):Pythonisusedforprogramming
IoTdevicesandmanagingreal-timedata.
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Interoperability:
Pythoncanintegratewithotherlanguages(e.g.,C,C++,
Java)forspecificusecases,allowingdeveloperstousethe
besttoolforeachtask.
WhoUsesPython?
Companies:Google,Facebook,Instagram,Netflix,Spotify,
NASA,andmanymore.
Domains:Finance,healthcare,entertainment,education,
e-commerce,andmore.
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PYTHON ORIGINS

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WorkonPythonbeganinlate1989byGUIDOVAN
ROSSUM.
Itwaseventuallyreleasedforpublicdistributionin
early1991.
LikeC,C++,Lisp,JavaandPerl,Pythoncamefroma
researchbackgroundwheretheprogrammerwas
havingahardtimegettingthejobdonewiththe
existingtoolsathandandenvisionedanddevelopeda
betterway.
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ItwasnamedaftertheMontyPythoncomedy
group.
Pythonisahigh-level,interpretedlanguagethatwas
designedforcodereadabilityandeaseofuse.
Itisusedforawiderangeofapplications,including
webdevelopment,scientificcomputing,data
analysis,artificialintelligence,andmore.
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PYTHON OVERVIEW and
FEATURES

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Thecodewritteninpythonisautomatically
compiledtobytecodeandexecuted.
Pythoncanbeusedasascriptinglanguage,asa
languageforimplementingwebapplicationsetc.
ExtendingpythonwithCorC++canhelpinthe
performanceofintensivetaskswherespeedof
executionisakeycriterion.
Pythonsupportsmanyfeaturessuchasnestedcode
blocks,functions,classes,modulesandpackages.
Pythonmakesuseofanobject-oriented
programmingapproach.
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FEATURESARE:
1.HighLevel
2.ObjectOriented
3.Scalable
4.Extensible
5.Portable
6.EasytoLearn
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7.EasytoRead
8.EasytoMaintain
9.Robust
10.EffectiveasaRapid
PrototypingTool
11.AmemoryManager
12.InterpretedandByte-
Compiled

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1.HighLevel:
•Pythonisanobject-oriented,high-level
programminglanguage.
•Object-orientedmeansthislanguageisbased
aroundobjects(suchasdata)ratherthan
functions,andhigh-levelmeansit'seasyfor
humanstounderstand.
•PythonLists(resizeablearrays)anddictionaries
(hashtables)arebuiltintothelanguage.
•Minimizesdevelopmenttimeandcodesize–
readablecode.
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28. BCA
2.ObjectOriented:
•InPython,object-orientedProgramming(OOPs)
isaprogrammingparadigmthatusesobjectsand
classesinprogramming.
•Itaimstoimplementreal-worldentitieslike
inheritance,polymorphisms,encapsulation,etc.
intheprogramming.
•PythonisnotjustanOOlanguagelikeJava/
Ruby,itisamixofmultipleprogramming
paradigms,likeitborrowsafewthingsfrom
functionallanguageslikeLispandHaskell.
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29. BCA
3.Scalable:
•Codereusability
•Addotherneworexistingpythonelements
•Encouragescleancodedesign
•Highlevelstructureandpackagingofmultiple
components–deliversflexibility,consistencyand
fasterdevelopmenttime.
•Scalablereferstomeasuringh/wthroughput
andadditionalperformancewhennewh/wis
addedtothesystem.
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30. BCA
4.Extensible:
•Aprogramminglanguageissaidtobeextensible
ifitcanbeextendedtootherlanguages.
•Pythoncodecanalsobewritteninother
languageslikeC(Cpython),C++,Java(Jython),C#
orVB.NET(IronPython)makingitahighly
extensiblelanguage.
•Ifpythoncodeincreases,codecanbeseparated
intomultiplefilesormodulesandbeableto
accesscodefromonemoduleandattributes
fromanother.
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31. BCA
5.Portable:
•Pythonisportableinthesensethatthesame
codecanbeusedondifferentmachines.
•SupposeyouwriteaPythoncodeonaMac.Ifyou
wanttorunitonWindowsorLinuxlater,you
don'thavetomakeanychangestoit.
•Assuch,thereisnoneedtowriteaprogram
multipletimesforseveralplatforms.
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32. BCA
6.EasytoLearn:
•Pythonisactuallyoneofthebestprogramming
languagesforbeginners.
•ItssyntaxissimilartoEnglish,whichmakesit
relativelyeasytoreadandunderstand.
•Withsometimeanddedication,youcanlearnto
writePython,evenifyou'veneverwrittenaline
ofcodebefore.
•Pythonhasfewkeywords,simplestructureand
clearlydefinedsyntax.
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33. BCA
7.EasytoRead:
•Becausethereadabilityandotherstructural
elementsofPythonaredesignedtobeeasyto
understand,especiallyforEnglishspeakers,it's
relativelyeasytolearn.
•Thisisagreatfirstorsecondlanguagefor
beginners.However,Pythonisnotlimitedto
basicuse.
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8.EasytoMaintain:
•Maintainingsourcecodeispartofthesoftware
developmentlifecycle.
•Easy-to-maintain−Python'ssourcecodeisfairly
easy-to-maintain.
•Abroadstandardlibrary−Python'sbulkofthe
libraryisveryportableandcross-platform
compatibleonUNIX,Windows,andMacintosh.
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35. BCA
9.Robust:
•Robustprogrammingisastyleofprogramming
thatfocusesonhandlingunexpectedtermination
andunexpectedactions.
•Itrequirescodetohandletheseterminations
andactionsgracefullybydisplayingaccurateand
unambiguouserrormessages.
•Theseerrormessagesallowtheusertomore
easilydebugtheprogram.
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36. BCA
10.EffectiveasaRapidPrototypingTool:
•PythonhasasimplesyntaxsimilartotheEnglish
language.
•Pythonhassyntaxthatallowsdevelopersto
writeprogramswithfewerlinesthansomeother
programminglanguages.
•Pythonrunsonaninterpretersystem,meaning
thatcodecanbeexecutedassoonasitiswritten.
•Thismeansthatprototypingcanbeveryquick.
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37. BCA
11.AMemoryManager:
•MemorymanagementinPythoninvolvesaprivate
heapcontainingallPythonobjectsanddata
structures.
•Themanagementofthisprivateheapisensured
internallybythePythonmemorymanager.
•Theprogrammerhastomanuallyallocatememory
beforeitcanbeusedbytheprogramandreleaseit
whentheprogramnolongerneedsit.
•InPython,memorymanagementisautomatic!
Pythonautomaticallyhandlestheallocationand
deallocationofmemory.
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38. BCA
12.InterpretedandByteCompiled:
•Pythonisclassifiedasaninterpretedlanguage,
meaningthatcompile-timeisnolongerafactor
duringdevelopment.
•Interpretedlanguagesareslowerthancompiled
languagesbecauseexecutiondoesnottakeplacein
asystem’snativebinarylanguage.
•LikeJava,Pythonisbyte-compiled,resultinginan
intermediateformclosertoMachineLanguage.
ThisimprovesPython’sperformance,allowsitto
retainalltheadvantagesofinterpretedlanguages.
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39. BCA
Pythonhasseveraladditionalfeatures
whichareasfollows:
•Ithasmanybuilt-indatatypes,strings,
lists,tuples,dictionaries,etc.
•Itsupportsmanycontrolstatements
suchasif,if-else,if–elseif-else,while,
iterativefor,etc.
•Itallowsforeasierprogrammingwith
theuseoffunctions,classes,modules
andpackages.
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40. BCA
PythonSyntaxcomparedtoother
programminglanguages:
Pythonwasdesignedforreadability,andhas
somesimilaritiestotheEnglishlanguagewith
influencefrommathematics.
Pythonusesnewlinestocompleteacommand,as
opposedtootherprogramminglanguageswhich
oftenusesemicolonsorparentheses.
Pythonreliesonindentation,usingwhitespace,to
definescope;suchasthescopeofloops,functions
andclasses.Otherprogramminglanguagesoften
usecurly-bracketsforthispurpose.
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41. BCA
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•ThemostrecentmajorversionofPython
isPython3.
•However,Python2,althoughnotbeing
updatedwithanythingotherthan
securityupdates,isstillquitepopular.
•ItispossibletowritePythoninan
IntegratedDevelopmentEnvironment,
suchasThonny,Pycharm,Netbeansor
Eclipsewhichareparticularlyuseful
whenmanaginglargercollectionsof
Pythonfiles.

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43. BCA
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PYTHON A SCRIPTING
LANGUAGE

44. BCA
–Pythonisahigh-level,interpretedscriptinglanguagethat
iswidelyusedforavarietyofprogrammingtasks.It
emphasizescodereadabilityandsimplicity,makingita
greatchoiceforbothbeginnersandexperienced
developers.
»Interpreted:Pythoncodeisexecutedlinebyline,which
makesiteasiertodebugandtest,comparedtocompiled
languages.
»DynamicallyTyped:Youdon'tneedtodeclarevariable
typesexplicitly.Theinterpreterinfersthetypeofavariable
atruntime,whichcontributestofasterdevelopmentbut
mayleadtoruntimeerrorsiftypesaremismatched.
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45. BCA
»ReadableSyntax:Python'ssyntaxisdesignedtobe
readableandclear,reducingthecomplexityofwritingand
understandingcode.Forexample,indentationisusedto
definecodeblocksinsteadofbraces{}.
»Cross-Platform:Pythonisavailableonmultipleplatforms
(Windows,Linux,MacOS)andallowsdeveloperstowrite
cross-platformscripts.
»ExtensiveLibraries:Pythonhasalargestandardlibrary,
whichmeansmanytasks(filehandling,database
connections,webscraping,etc.)canbedonewithminimal
externaldependencies.Additionally,Pythonhasarobust
ecosystemofthird-partylibraries.
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46. BCA
»Object-Oriented:Pythonsupportsobject-oriented
programming(OOP)concepts,whichmakesiteasierto
structureprogramsinamodularway.
»Versatile:Pythonisusedinawidevarietyoffields
includingwebdevelopment(e.g.,Django,Flask),data
analysis(e.g.,Pandas,NumPy),automation(e.g.,scripting
tasks),artificialintelligence(e.g.,TensorFlow,Keras),and
more.
»High-Level:Asahigh-levellanguage,Pythonabstractsaway
mostofthecomplexdetailsofcomputeroperations,
allowingdeveloperstofocusmoreonlogicthanonsystem-
specificdetails.
»CommunitySupport:Pythonhasanactiveandlarge
communityofdeveloperswhocontributetotutorials,
forums,andopen-sourceprojects.
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USERS OF PYTHON

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–Awiderangeoffinancialinstitutions,techcompanies,
governmentagencies,andmorelookforcandidateswho
haveamasteryofPythonforroleswithinwebandsoftware
developmentanddatascience,amongothers.
–Generallyspeaking,PythonDevelopers(sometimesjust
referredtoasWebDevelopers,or,morepreciselyBack-End
Developers)usePythontodevelopwebsites,applications,
games,andmore.
–DataScientistsusePythonforcomputinglargeamountsof
dataanddrawingfromlargedatabasesandlibraries.It’s
particularlyusefulforthosewhospecializeinmachine
learningasPythonisabletoaccessmachinelearning
frameworksforthoseworkingwithAI.
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62. BCA
–PythonisusedbyIntel,IBM,NASA,Pixar,Netflix,Facebook,
JPMorganChase,Spotify,andanumberofothermassive
companies.
–It’soneofthefourmainlanguagesatGoogle,whileGoogle’s
YouTubeislargelywritteninPython.
–SamewithReddit,Pinterest,andInstagram.
–TheoriginalBitTorrentclientwasalsowritteninPython.
–AnditisusedasascriptinglanguagetocontrolMaya,the
industrystandard3Dmodelingandanimationtool.
–Pythonisusedheavilyinacademicresearch,particularlyin
bioinformatics,biology,andmathematics.
–Itisthestandardintroductorylanguageformany
universitycomputerscienceprograms.
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63. BCA
–SomeofthemaingroupsandsectorsthatusePythontoday:
»SoftwareDevelopers:Forwebdevelopment(Django,
Flask)andautomationscripting.
»DataScientistsandAnalysts:Fordataanalysis,
manipulation,andvisualization(Pandas,NumPy).
»ResearchersandAcademics:Forscientificresearchand
simulationsinvariousfields.
»FinancialAnalysts:Forquantitativeanalysis,financial
modeling,andalgorithmictrading.
»DevOpsEngineers:Forautomatingdeployment
pipelinesandinfrastructuretasks.
»CybersecurityProfessionals:Forpenetrationtesting
andcreatingsecuritytools.
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64. BCA
»EmbeddedSystemsEngineers:Forscriptingon
microcontrollersandembeddeddevices(MicroPython).
»ScientistsandEngineers:Forsimulations,modeling,
anddataanalysis.
»BigTechCompanies:UsedbycompanieslikeGoogle,
Instagram,Spotify,Netflix,andDropbox.
»StartupsandEntrepreneurs:Forrapidprototypingand
productdevelopment.
»GovernmentandNonprofits:Fordataanalysisand
automatingadministrativetasks.
»Education:Widelyusedtoteachprogrammingin
schools,universities,andcodingbootcamps.
»AI&Robotics:ForAIapplications,computervision,and
roboticsdevelopment.
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65. BCA
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NEED OF PYTHON

66. BCA
–SimplicityandReadability:Python’ssyntaxisclean,easyto
read,andintuitive,makingitidealforbeginnersand
experienceddevelopersalike.Itreducesthecomplexityof
code,speedingupdevelopmenttime.
–Versatility:Pythoncanbeusedforawiderangeof
applications,includingwebdevelopment,dataanalysis,
machinelearning,automation,AI,scientificcomputing,and
more.Itsadaptabilitymakesitago-tolanguageforvarious
domains.
–LargeCommunityandEcosystem:Pythonhasavast
communityofdevelopers,whichmeansthereisawealthof
tutorials,resources,andthird-partylibraries(e.g.,NumPy,
TensorFlow,Django)availabletosupportdevelopment.
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67. BCA
–Cross-PlatformCompatibility:Pythonisavailableonall
majoroperatingsystems(Windows,Linux,macOS)andcan
runonmultipleplatformswithoutsignificantchangesto
thecodebase.
•Extensive Libraries and Frameworks: Python’s rich set of
libraries and frameworks simplifies complex tasks like web
scraping (BeautifulSoup), machine learning (Scikit-learn,
TensorFlow), and data manipulation (Pandas, NumPy).
•Rapid Prototyping: Python allows quick prototyping and
iterative development. Its ease of use means ideas can be
tested and refined quickly, which is essential for startups
and innovation-driven industries.
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68. BCA
–IntegrationCapabilities:Pythonintegrateswellwithother
languages(likeC,C++,andJava),systems,andtools.Italso
workswellwithdatabasesandwebservices,makingit
suitableforcomplexsystemdevelopment.
–PopularityinEmergingFields:Pythoniscrucialinrapidly
growingfieldssuchasartificialintelligence(AI),data
science,machinelearning,deeplearning,andautomation,
makingitanessentiallanguageformoderntechnological
advancements.
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69. BCA
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PYTHON’S TECHNICAL
STRENGTHS

70. BCA
–ItsRelativelyEasytouse.
–Itsfree
–Itsportable
–Itsgeneralpurposelanguage
–Itspowerful
–Dynamictyping
–Automaticmemorymanagement
–Programminginthelargesupport
–Built-inobjecttypes
–Built-inoperation
–Libraryutilitiesandthirdpartyutilities
–Itsmixable
–Itsobject-orientedandfunctional
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HOW PYTHON RUNS
PROGRAMS:
INTRODUCING THE
PYTHON
INTERPRETER

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How Python
Programs Works?

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–APythonprogramstartsasatextfile
writteninacodeeditor,savedwith
a.pyextension.
–ThePythoninterpreterreadsthissource
code,analyzesit,andexecutesitlineby
line.
–Duringthisprocess,itperformslexical
analysis,parsing,andexecution.
–Optionally,thesourcecodecanbecompiled
intobytecodeforfasterexecution.
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79. BCA
–ThePythoninterpreteractsasavirtual
machine,executingthecodebyconverting
itintomachine-specificbinarycode.
–Theprogrammayutilizelibrarymodules
forvarioustasks.
–Whenrun,itcaninteractwiththesystem,
processdata,andproduceoutput.
–Anyerrorsorexceptionsarehandled
duringexecution.
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80. BCA
–Pythonisahigh-levelprogramminglanguage
knownforitssimplicityandreadability.
CodeEditor:
–YoustartbywritingyourPythoncodeina
codeeditor.
–Thisiswhereyoucreateyourprogramand
saveitwitha.pyextension.
–Acodeeditorprovidesfeaturesforwriting
andeditingcode,suchassyntaxhighlighting
andcodecompletion.
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81. BCA
–Openatexteditor,andwritethefollowing
code:
print("Hello,World!")
SourceFile:
–YourPythoncodeissavedinasourcefilewith
a.pyextension,e.g.,hello.py.Thisfilecontains
thetextofyourprogramwritteninPython's
syntax.
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82. BCA
Compiler(Optional):
–Pythonistypicallyaninterpretedlanguage,
meaning itdoesn'trequireexplicit
compilationbeforerunning.
–Insomecases,yourPythoncodemaybe
compiledintobytecode.
–Thiscompiledbytecodeissavedin.pycfiles.
–Thecompilationisnotsomethingyouusually
domanually;it'smanagedbythePython
interpreter.
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83. BCA
Bytecode:
–Bytecodeisanintermediaterepresentationof
yourPythoncode.
–It'salow-level,platform-independentformat
thatthePythoninterpretercanexecute.
–Bytecodefiles(.pyc)aregeneratedtoimprove
executionspeed.
–Ifthe.pycfileexistsandisnewerthanthe
sourcecode,Pythonusesitforfaster
execution.
–Inthecaseof"Hello,World!"wherethecode
issimple,Pythonoftenskipsthebytecode
step.
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84. BCA
PythonInterpreter(VirtualMachine):
–ThePythoninterpreterisresponsiblefor
executingyourPythoncode.Youexecutethe
Pythonprograminyourterminalor
commandprompt.
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python hello.py

85. BCA
ThePythoninterpreterreadshello.pyandperforms
severalstepsduringtheexecution:
–LexicalAnalysis:Itisthefirstphaseofacompiler
orinterpreterwherethesourcecodeisscanned
andbrokenintotokens.Itinvolvesidentifyingthe
basicbuildingblocksofaprogram,suchas
keywords,identifiers,operators,literals,and
punctuation.
–Parsing:Itconstructsaparsetreetounderstand
thecode'sstructureandlogic.
–Execution:Itexecutestheprogrambyfollowingthe
instructionsdefinedintheparsetree.Thisincludes
performingcalculations,I/Ooperations,and
functioncalls.
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86. BCA
LibraryModules:
–Pythonprovidesarichstandardlibrary,
whichincludesawiderangeofmodulesand
functionsforvarioustasks.
–Youcanimporttheselibrarymodulesinto
yourprogramtoextenditsfunctionality.
–Forexample,themathmoduleprovides
mathematicalfunctions,andtheosmodule
allowsyoutointeractwiththeoperatingsystem.
–Whilethe"Hello,World!"exampledoesn'tuseany
additionalmodules,youcanimportandusethem
inmorecomplexprogramstoextend
functionality.
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87. BCA
•Data Science & Machine Learning:
–NumPy:Fornumericaloperationsandmulti-
dimensionalarrays.Alibraryforscientificand
technicalcomputing,usedinlinearalgebra,statistical
analysis,andmachinelearning
–Pandas:For data manipulation and analysis.
–Matplotlib:For data visualization. A library for
creating static, animated and interactive
visualizations.
–SciPy:For scientific and technical computing.
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88. BCA
–TensorFlow:Formachinelearninganddeep
learning.Alibraryforhigh-levelcomputations,
machinelearning,deeplearningalgorithms,and
solvingcomplexmathematicalandphysicsproblems.
–PyTorch:Another popular machine learning and
deep learning library. This involves NLP or CV.
–Scikit-learn:For machine learning algorithms and
tools.
–PyGame: A package that provides an interface to the
Simple Directmedia Library (SDL) for graphic, audio,
and input libraries.
–Keras: A library for experimenting with deep neural
networks.
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89. BCA
•Web Development:
–Django:A high-level web framework for building
complex web applications.
–Flask:A micro web framework for building smaller,
simpler web applications.
•Web Scraping:
–BeautifulSoup:For extracting data from HTML and
XML files.
–Scrapy:A powerful framework for web scraping and
crawling.
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90. BCA
•Web Development:
–Django:A high-level web framework for building
complex web applications.
–Flask:A micro web framework for building smaller,
simpler web applications.
•Web Scraping:
–BeautifulSoup:For extracting data from HTML and
XML files.
–Scrapy:A powerful framework for web scraping and
crawling.
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91. BCA
•Other:
–Requests:For making HTTP requests.
–Pillow:For image processing.
–OpenCV:For computer vision.
–NLTK:For natural language processing.
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92. BCA
BinaryCode:
–ThePythoninterpreterconvertsthebytecode
intomachinecodethatisspecifictoyour
computer'sarchitecture.Thisisdone
dynamicallyduringtheexecutionofyour
Pythonprogram.
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93. BCA
RunningProgram:
–AsthePythoninterpreterexecutesthe
bytecode,yourPythonprogramruns,andit
caninteractwiththesystem,readandwrite
files,andproduceoutput.
–Ifthereareerrorsorexceptions,Pythonwill
handlethemaccordingtoyourcodeorraise
anerrorifnotcaught.
–Inthisexample,theprogramwillrunand
displaytheoutput:
Hello,World!
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94. BCA
Completion
Theprogramexecutioncompletes,having
successfullyprintedHello,World!totheconsole.If
therewereerrorsorexceptionsinthecode,Python
wouldhandlethemaccordingly.
InthecaseofHello,World!,theprocessisrelatively
simple.Youwritethecodeinacodeeditor,saveitas
asourcefile,andexecuteitusingthePython
interpreter.Pythoninterpretsandexecutesthecode,
displayingtheoutput.ComplexPythonprograms
followasimilarprocess,withmoreintricatelogic
andpossiblytheuseoflibrarymodules.
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95. BCA
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Introducing the
Python Interpreter

96. BCA
Dr. Reshmi. S I BCA B 96
DEC-MAR 2025

97. BCA
Dr. Reshmi. S I BCA B 97
DEC-MAR 2025

98. BCA
•What are Interpreters?
–Interpretersarethecomputerprogramthat
willconvertthesourcecodeoranhighlevel
languageintointermediatecode(machine
levellanguage).
–Itisalsocalledtranslatorinprogramming
terminology.
–Interpretersexecuteseachlineofstatements
slowly.ThisprocessiscalledInterpretation.
–Forexample:Pythonisaninterpreted
language,PHP,Ruby,andJavaScript.
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99. BCA
Dr. Reshmi. S I BCA B 99
DEC-MAR 2025

100. BCA
•Example:
Here is the simple Python program that takes
two inputs asaandband prints the sum in the
third variable which isc. It follows sequential as
well as functional execution of programs
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101. BCA
•How interpreters function in Python?
–PythoninterpreteriswritteninC
programminglanguageasweallknowthatC
isconsideredasmotherofallprogramming
languages,Pythoninterpretercalled
"CPython".
–Initiallyinsourcecodeanalysis,Pythonget
sourceandcheckforsomeIndentationrule
andcheckforerrors.
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102. BCA
–IfthereareanyerrorsPythonstopsitsexecution
andmaketomodifytopreventerrors.This
processiscalledLexicalanalysisinpythonwhich
statesthatdividingthesourcecodeintolistof
individualtokens.
–InBytecodegeneration,oncethepython
interpreterreceivesthetokens,itgeneratesAST
(AbstractStructuretree)whichconvertstobyte
codeandthenbytecodecanbesavedin(.py)
extension.
–Atlast,byusingPythonVirtualMachine,
interpreterloadsthemachinelanguageandPVM
convertsininto0sand1swhichprintsthe
results.
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103. BCA
–BYTECODE:
»BytecodeinPythonreferstoanintermediate,
low-levelrepresentationofPythoncodethatis
executedbythePythonVirtualMachine(PVM).
Itisaseriesofinstructionsthataregenerated
afterthePythonsourcecodeiscompiled.
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104. BCA
DEC-MAR 2025 Dr. Reshmi. S I BCA B 104
Difference between
Compilers and
Interpreters

105. BCA
Dr. Reshmi. S I BCA B 105
DEC-MAR 2025
COMPILER INTERPRETER
Ittranslatesaprogramona
singlerun
Itexecutesaprogramlinebyline.
ItisanFastProcess ItisanSlowProcess
Itgeneratesoutputintheformof
.(exe)
Itdoesnotgenerateanyformof
outputs.
ItutilizesCPUmore. IttakeslessutilizationofCPU
ItisusedinProduction
environment
Itismaximum usedin
Programminganddevelopment
environment.
C,C++,C#arethecompiled
languages
Python,Ruby,PHParethe
interpretedlanguages.
Ittakeslotoftimetoanalyzethe
codestructure
Ittakeslesstimecomparedto
compilers.

106. BCA
•AdvantagesofusingInterpreter
–Itisflexibleanderrorlocalizationiseasier.
–Itissmallerinsize.
–Itexecuteslinebylineexecution.
•DisadvantagesofusingInterpreters
–Ittakeslotoftimetotranslate.
–Itisslower.
–Ituseslotofstorage.
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107. BCA
•ApplicationsofInterpreters
–Theyareusedtoexecutecommonlanguagesby
usingeditororancompiler.
–Easyimplementationofselfmodifyingcode.
–Virtualization.
–Sandboxing.
–Emulators.
•Interpretersofdifferentprogramminglanguage.
–Python-PyPy,StacklessPython,Pyston,
CPython,MicroPython,andRustPython.
–Java-JRocklt,Hotspot.
–Ruby-CRuby,MRI.
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108. BCA
DEC-MAR 2025 Dr. Reshmi. S I BCA B 108
GETTING STARTED WITH PYTHON

109. BCA
BeginningwithPythonprogramming:
1)FindinganInterpreter
2)Writingfirstprogram
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2025
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110. BCA
1)FindinganInterpreter:
–BeforewestartPythonprogramming,we
needtohaveaninterpretertointerpretand
runourprograms.
–Therearecertainonlineinterpreterslike
»https://ide.geeksforgeeks.org/
»http://ideone.com/
»http://codepad.org/thatcanbeusedto
startPythonwithoutinstallingan
interpreter.
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111. BCA
–Windows:Therearemanyinterpreters
availablefreelytorunPythonscriptslike
IDLE (Integrated Development
Environment)whichisinstalledwhenyou
installthepythonsoftwarefrom
http://python.org/
–Linux:ForLinux,Pythoncomesbundled
withtheLinux.
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112. BCA
1)WritingFirstProgram:
–FollowingisfirstprograminPython
# Script Begins
print(“Welcome")
# Scripts Ends
DEC-MAR 2025 Dr. Reshmi. S I BCA B 112
OUTPUT:
Welcome

113. BCA
–Line1:[#ScriptBegins]
»InPythoncommentsbeginwith#.Sothisstatementis
forreadabilityofcodeandignoredbyPython
interpreter.
–Line2:[print(“Welcome”)]
»InaPythonscripttoprintsomethingontheconsole
print()functionisused–itsimplyprintsoutaline(and
alsoincludesanewlineunlikeinC).
»OnedifferencebetweenPython2andPython3isthe
printstatement.InPython2,the“print”statementisnot
afunction,andthereforecanbeinvokedwithouta
parenthesis.However,inPython3,itisafunction,and
mustbeinvokedwithparentheses.
–Line3:[#ScriptEnds]
»ThisisjustanothercommentlikeLine1.
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114. BCA
Threedifferentwaysofstarting
Python:
–Runningascriptwritteninpython
–UsingaGUIfromanIntegrated
DevelopmentEnvironment(IDE)
–Employinganinteractiveapproach
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115. BCA
•TheFirstapproachwillrequireaTEXT
EDITOR.Createourownscriptsandthen
executethemusingtheTextEditor.
•TheSecondapproachwillrequireaGUI
application,onethatcomeswiththePython
installeritself.
•TheThirdinteractiveapproachiscommand
lineinterpreterwhichisprovidedby
python.
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116. BCA
INSTALLING PYTHON INTERPRETER
a)InstallingonLinuxOS:
1.Downloadthe.tgzfileofPythonfromtheaboveprovided
downloadlink.
http://www.python.org/ftp/python/2.7.11/Python-2.7.11.tgz
2.Unzipthedownloadedfile.
tarxvfzPython-2.7.11.tgz
3.Gointothedirectory.
cdPython-2.7.11
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117. BCA
4../configure
5.Buildit
6.Make
7.suorsudosuifthereisnorootuser
8.Makealtinstall
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118. BCA
b)InstallingonWindowsOS:
•Firstofall,youneedtodownloadthePythonInstallerfrom
thelink:http://www.Python.org/downloads/
•Next,doubleclickontheinstalledfile.Astheinstaller
begins,youwillbeaskedtoselecttheusersforwhomyou
wanttheprogramstobeinstalled.
•ChooseInstallforallusersandclickNext>.
Note:Installingforallusersisrecommended.
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119. BCA
•Nowchoosethedirectorywhereyouwanttoinstall
PythonandclickNext>.Itisbesttousethedefaultgives
location.
•Youwillbethenaskedtoselectthepackage.ClickNext>
•Pleasenotethatinstallationtakessometimeto
complete.
•Oncetheinstallationprocessiscomplete,clickonFinish
toexittheinstaller.
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120. BCA
Pythonisnowinstalledinyourcomputer’s
directory.YouneedtorunPythonbyfollowing
thegivensteps:
1.ClickSTARTbutton.
2.GotoAllPrograms
3.SearchforPython2.7folder.
4.ClickPython(Commandline)
ThiswillstartthePythonCommandline.
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121. BCA
OncePythonstarts,youwillseetheinterpreterstartup
message,indicatingversionandplatform.
Youwillalsobegiventhepythoninterpreterprompt,i.e.,
“>>>”whichisalsoknownaspythonchevronprompt.
The“>>>”indicatesthatpythoninterpreteriswaitingfor
anexpressionorcommand.
Theinteractiveenvironmentwhereweareinteractingwith
thepythoninterpreteriscalledtheconsoleorcommand
shell.
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122. BCA
•Enterasimpleexpression8+9,ontheconsole.After
enteringtheexpression,presstheEnterkeytogettheresult.
>>>8+9
17 #Output
>>>
•TypethefollowingtextatthePythonpromptsandpress
Enter
>>>print(“Hello,Python!”)
Hello,Python!#Output
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123. BCA
•Theprintstatementisusedtodisplayoutput
tothescreen.
•Manyshellscriptlanguagesusetheecho
commandforprogramoutput.
•Theprintstatement,pairedwiththestring
formatoperator(%),behavesevenmorelike
C’sprintf()function.
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124. BCA
Dr. Reshmi. S I BCA B 124
DEC-MAR 2025

125. BCA
Dr. Reshmi. S I BCA B 125
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126. BCA
Dr. Reshmi. S I BCA B 126
DEC-MAR 2025

127. BCA
Dr. Reshmi. S I BCA B 127
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128. BCA
Dr. Reshmi. S I BCA B 128
DEC-MAR 2025

129. BCA
Dr. Reshmi. S I BCA B 129
DEC-MAR 2025

130. BCA
Dr. Reshmi. S I BCA B 130
DEC-MAR 2025

131. BCA
Dr. Reshmi. S I BCA B 131
DEC-MAR 2025

132. BCA
Dr. Reshmi. S I BCA B 132
DEC-MAR 2025

133. BCA
Dr. Reshmi. S I BCA B 133
DEC-MAR 2025

134. BCA
Dr. Reshmi. S I BCA B 134
DEC-MAR 2025

135. BCA
Dr. Reshmi. S I BCA B 135
DEC-MAR 2025

136. BCA
Dr. Reshmi. S I BCA B 136
DEC-MAR 2025
Wheneveryouaredoneinthepython
commandline,youcansimplytypethe
followingtoquitthepythoncommand
lineinterface:
exit()

137. BCA
DEC-MAR 2025 Dr. Reshmi. S I BCA B
137
COMMENTS

138. BCA
•Justlikeotherprogramminglanguages,Python
allowsyoutoaddcommentsinthecode.
•Commentsareusedbytheprogrammertoexplain
thepieceofcodetoothersaswellastohimselfina
simplelanguage.
•Pythonusesthehashcharacter(#)forcomments.
•Putting#beforeatextensuresthatthetextwillnot
beparsedbytheinterpreter.
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139. BCA
•Commentsdonotaffecttheprogrammingpartand
thePythoninterpreterdoesnotdisplayanyerror
messagesforcomments.
•Commentsshowupasitisintheprogramming.
•Itisagoodpracticetousecommentsforprogram
documentationinyourprogramsothatitbecomes
easierforotherprogrammerstomaintainor
enhancetheprogramwhenrequired.
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140. BCA
ExamplesofComments:
CommentingwithouttheuseofHashmark(#):
>>>8+9addition
SyntaxError:invalidsyntax #Output
>>>
Intheaboveexample,‘addition’iswrittenwithout
theHashmark.
Asaresult,theinterpreteracceptstheword
‘addition’aspartofprogramming.
Since‘addition’isnotacommandinPython,an
errormessageisdisplayed.
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141. BCA
CommentingusingHashmark(#):
>>>8+9#addition
17 #Output
>>>
Now,inthisexample,‘addition’iswrittenwitha
Hashmark.
Hence,theinterpreterunderstandsitasacomment
anddoesnotdisplayanyerrormessage.
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142. BCA
1.WhatareComments?
–Commentsareannotationsmadebythe
programmer.
–Thesehelpotherprogrammers in
understandingthecode.
2.Whichcharacterisusedforcommenting
inPython?
–Hashmark(#)isusedforcommentingin
Python
DEC-MAR 2025
Dr. Reshmi. S I BCA B 142

143. BCA
DEC-MAR 2025 Dr. Reshmi. S I BCA B
143
PROGRAM
EXECUTION

144. BCA
Dr. Reshmi. S I BCA B 144
DEC-MAR 2025

145. BCA
InPython,programexecutionreferstotheprocess
ofrunningaPythonscriptorprogram,which
involvesinterpretingthePythoncodeand
performingthetasksdescribedinthecode.
Pythonprogramexecutionworksstepbystep:
1.WritingaPythonScript
2.ExecutingtheProgram
3.BehindtheScenes:HowPythonExecutesaProgram
4.ErrorsDuringExecution
5.ToolstoDebugPythonExecution
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146. BCA
DEC-MAR 2025
Dr. Reshmi. S I BCA B 146
1.WritingaPythonScript:
YouwriteaPythonprograminafilewiththe
extension.py.Forexample:
#hello.py
print("Hello,World!")

147. BCA
2.ExecutingtheProgram:
Youcanruntheprograminvariousways:
UsingtheCommandLine(Terminal):
–Opentheterminalorcommandprompt.
–NavigatetothedirectorycontainingyourPythonfile.
–Runthecommand:
pythonhello.py
–Output:
Hello,World!
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148. BCA
UsinganIntegratedDevelopmentEnvironment(IDE):
–OpenthescriptinanIDElikePyCharm,VisualStudioCode,
Thonny,orIDLE.
–Clickthe"Run"buttontoexecutethescript.
–Output:
Hello,World!
UsingOnlineInterpreters:
–Youcanalsopasteyourcodeintoonlineplatformslike
Replit,JupyterNotebook,orGoogleColabandexecuteit
there.
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149. BCA
3.BehindtheScenes:HowPythonExecutesaProgram:
LexicalAnalysis:
Theinterpreterbreaksthecodeintotokens(keywords,
operators,etc.).
Parsing:
ThetokensaregroupedintoastructurefollowingPython's
grammarrules(AbstractSyntaxTree-AST).
Compilation:
Thecodeisconvertedintoanintermediateformcalled
bytecode.
Example:Forprint("Hello,World!"),Pythongeneratesbytecode
instructions.
ExecutionbyPythonVirtualMachine(PVM):
ThebytecodeisexecutedbythePythonVirtualMachine(PVM),
translatingtheinstructionsintomachinecodeforthehardware.
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150. BCA
Dr. Reshmi. S I BCA B 150
DEC-MAR 2025
Example: Python Execution Flow
Consider this program:
x = 10
y = 20
print("The sum is:", x + y)

151. BCA
Dr. Reshmi. S I BCA B 151
DEC-MAR 2025
Execution Steps
1.Lexical Analysis:
•The code is tokenized into parts like x, =, 10, y, 20,
print, etc.
2.Parsing:
•Python creates a syntax tree representing the structure
of the program.
3.Bytecode Generation:
•Python compiles the code into .pyc(bytecode).
4.Execution:
•The PVM executes the bytecode and prints:
The sum is: 30

152. BCA
4.ErrorsDuringExecution:
Pythonhandlesthreemaintypesoferrors:
1.SyntaxErrors:Errorsincodestructure.
print"Hello"#Missingparentheses
2.RuntimeErrors:Errorsduringprogram
execution.
print(1/0)#Divisionbyzero
3.LogicalErrors:Theprogramrunsbutgives
incorrectresults.
x,y=10,20print("Product:",x-y)#Logical
mistake
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153. BCA
5.ToolstoDebugPythonExecution:
PrintStatements:Addprintstatementsto
debug.
Debugger:UsePythondebuggerslikepdb
orIDE-integratedtools.
StaticAnalysisTools:Toolslikepylintor
flake8forcodechecking.
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154. BCA
DEC-MAR 2025
Dr. Reshmi. S I BCA B
154
STANDARD
TYPES

155. BCA
Numbers
•Integer
Boolean
LongInteger
•Floatingpointrealnumber
•Complexnumber
String
List
Tuple
Dictionary
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156. BCA
DEC-MAR 2025
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156
OTHER BUILT-IN
TYPES

157. BCA
Type
NullObject(None)
File
Set/Frozenset
Function/Method
Module
Class
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158. BCA
•TypeObjectsandthetypeTypeObject–
Theamountofinformationnecessaryto
describeatypecannotfitintoasinglestring.
Callingtype()withanobject:
>>>type(42)
<type‘int’>
DEC-MAR 2025 Dr. Reshmi. S I BCA B 158
•Typeofalltypeobjectsistype.
>>>type(type(42))
<type‘type’>

159. BCA
•None,Python’sNullObject–
PythonhasaspecialtypeknownastheNull
objectorNoneType.
Ithasonlyonevalue,None.
ThetypeNoneisNoneType.
ItdoesnothaveanyoperatorsorBIF(Builtin
function).
Nonehasnousefulattributesandalways
evaluatestohavingaBooleanFalsevalue.
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160. BCA
DEC-MAR 2025
Dr. Reshmi. S I BCA B
160
STANDARD
TYPE
OPERATORS

161. BCA
1.OBJECTVALUECOMPARISON
2.OBJECTIDENTITYCOMPARISON
3.BOOLEAN
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162. BCA
1.OBJECTVALUECOMPARISON:
•Comparisonoperatorsareusedto
determineequalityoftwodatavalues
betweenmembersofthesametype.
•Thesecomparison operatorsare
supportedforallbuilt-intypes.
•ComparisonsyieldBooleanTrueorFalse
valuesbasedonthevalidityofthe
comparisonexpression.
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163. BCA
Dr. Reshmi. S I BCA B 163
DEC-MAR 2025

164. BCA
•AlistofPython’svaluecomparisonoperators:
DEC-MAR 2025 Dr. Reshmi. S I BCA B 164
OPERATOR FUNCTION
expr1< expr2expr1 is less than expr2
expr1> expr2expr1 is greater than expr2
expr1<= expr2expr1 is less than or equal to expr2
expr1>= expr2expr1 isgreaterthan or equal to expr2
expr1== expr2expr1 is equalto expr2
expr1!= expr2expr1 is not equal to expr2 (C-Style)
expr1<> expr2expr1 is not equal to expr2
(ABC/PascalStyle)

165. BCA
Numerictypeswillbecomparedaccordingtonumeric
valueinsignandmagnitude,stringswillcompare
lexicographically,etc..
Eg:
DEC-MAR 2025 Dr. Reshmi. S I BCA B 165
>>>2==2
True
>>>2.46<=8.33
True
>>>5+4j>=2-3j
True
>>>’abc’==‘xyz’
False
>>>’abc’>‘xyz’
False
>>>’abc’<‘xyz’
True
>>>[3,‘abc’]==[‘abc’,3]
False
>>>[3,‘abc’]==[3,‘abc’]
True

166. BCA
Multiplecomparisons–sameline:
Eg:
DEC-MAR 2025 Dr. Reshmi. S I BCA B 166
>>>3<4<7
True
>>>4>3==3
True
>>>4<3<5!=2<7
False

167. BCA
2.OBJECTIDENTITYCOMPARISON:
•Pythonsupportsthenotionofdirectly
comparingobjectsthemselves.
•Objectscanbeassignedtoothervariables
(byreference).
•Becauseeachvariablepointstothesame
(shared)dataobject,anychangeeffected
throughonevariablewillchangetheobject
andbereflectedthroughallreferencestothe
sameobject.
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168. BCA
•Eg:1
foo1andfoo2referencethesameobject
foo1=foo2=4.3
Bothfoo1andfoo2referencethesame
object.
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4.3
foo1
foo2

169. BCA
•Eg:2
foo1andfoo2referencethesameobject
foo1=4.3
foo2=foo1
Bothfoo1andfoo2referencethesame
object.
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4.3
foo1
foo2

170. BCA
•Eg:3
foo1andfoo2referencedifferentobjects
foo1=4.3
foo2=1.3+3.0
DEC-MAR 2025 Dr. Reshmi. S I BCA B 170
4.3
foo1
4.3
foo2

171. BCA
•Wecreateavariable,thenanotherthat
pointstothesameobject.
•Boththeisandnotidentifiersarepython
keywords.
>>>a=[5,‘hat’,-9.3]
>>>b=a
>>>aisb
True
>>>aisnotb
False
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>>>aisb
False
>>>aisnotb
True

172. BCA
•StandardTypeObjectIdentityComparison
Operators:
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OPERATOR FUNCTION
Obj1is obj2 Obj1is the same object as obj2
Obj1is not obj2Obj1is not the same object as obj2

173. BCA
3.BOOLEAN:
Expressionmaybelinkedtogetheror
negatedusingtheBooleanlogicaloperators
and,orandnotallofwhicharepython
keywords.
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174. BCA
•StandardTypeBooleanOperators:
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OPERATOR FUNCTION
notexpr Logical NOT of expr(negation)
expr1 and expr2LogicalAND of expr1 and expr2
(conjunction)
expr1 and expr2LogicalOR of expr1 and expr2
(disjunction)

175. BCA
>>>x,y=3.1415926536,1024
>>>x<5.0
True
>>>not(x<5.0)
False
>>>(x<5.0)or(y>2.718281828)
True
>>>(x<5.0)and(y>2.718281828)
False
>>>not(xisy)
True
>>>3<4<7sameas(3<4)and(4<7)
True
DEC-MAR 2025 Dr. Reshmi. S I BCA B 175

176. BCA
DEC-MAR 2025
Dr. Reshmi. S I BCA B
176
STANDARD
TYPE BUILT-IN
FUNCTIONS

177. BCA
•StandardTypeBuilt-inFunctions:
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FUNCTION OPERATION
cmp(obj1, obj2)Comparesobj1 and obj2 returns
integer iwhere i<0, i>0, i==0
repr(obj) Returns evaluatablestring
representation of obj
str(obj) Returns printablestring
representation of obj
type(obj) Determines type of objand return type
object

178. BCA
1.type()
•Syntaxfortype():
type(object)
•type()takesanobjectandreturnsitstype.
Thereturnvalueisatypeobject.
>>>type(4)
<type‘int’>
>>>type(‘HelloWorld!’)
<type‘string’>
>>>type(type(4))
<type‘type’>
DEC-MAR 2025 Dr. Reshmi. S I BCA B 178

179. BCA
2.cmp()
•Thecmp()BIFCoMParestwoobjects,obj1
andobj2andreturns
•anegativenumber(integer)ifobj1isless
thanobj2,
•apositivenumberifobj1isgreaterthan
obj2,
•Zeroifobj1isequaltoobj2
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180. BCA
•Thecomparisonusedistheonethatapplies
forthattypeofobject,whetheritbea
standardtypeorauser-createdclass.
DEC-MAR 2025 Dr. Reshmi. S I BCA B 180
>>>a,b=-4,12
>>>cmp(a,b)
-1
>>>cmp(b,a)
1
>>>b=-4
>>>cmp(a,b)
0
>>>a,b=‘abc’,‘xyz’
>>>cmp(a,b)
-23
>>>cmp(b,a)
23
>>>b=‘abc’
>>>cmp(a,b)
0

181. BCA
3.str()andrepr()(and‘‘operator):
str()STRingandrepr()REPResentation
BIFsorthesinglebackorreversequote
operator(‘‘).
>>>str(4.53-2j)
‘(4.53-2j)’
>>>str(1)
‘1’
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>>>str(2e10)
‘20000000000.0’
>>>repr([0,5,9,9])
‘[0,5,9,9]’

182. BCA
4.type()andisinstance():
•Pythondoesnotsupportmethodor
functionoverloading.
•Type()returnsthetypeforanyPython
object,notjustthestandardtypes.
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183. BCA
>>>type(‘‘)
<type‘str’>
>>>s=‘xyz’
>>>type(s)
<type‘str’>
>>>type(100)
<type‘int’>
>>>type(())
<type‘tuple’>
DEC-MAR 2025 Dr. Reshmi. S I BCA B 183
>>>type(0+0j)
<type‘complex’>
>>>type(0L)
<type‘long’>
>>>type(0.0)
<type‘float’>
>>>type([])
<type‘list’>
>>>type({})
<type‘dict’>

184. BCA
Python Type Operator and BIF Summary
DEC-MAR 2025 Dr. Reshmi. S I BCA B 184

185. BCA
Dr. Reshmi. S I BCA B 185
DEC-MAR 2025

186. BCA
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186
EXECUTION MODEL
VARIATION:
PYTHON
IMPLEMENTATION
ALTERNATIVES

187. BCA
DEC-MAR 2025 Dr. Reshmi. S I BCA B
187
Execution model
variation

188. BCA
InteractiveModeExecution
Codeisexecutedline-by-lineinthePython
interpreter.
Suitablefortestingandquickexperiments.
Example:
>>>print("Hello,World!")
Hello,World!
ScriptModeExecution
Codeisstoredina.pyfileandexecutedasawhole.
Suitableforfull-fledgedprograms.
Execution:
pythonscript.py
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189. BCA
ModuleImportExecution
Codeisstoredinamodule(.pyfile)andexecuted
indirectlythroughimport.
Onlytop-levelstatementsareexecutedduringimport.
Example:
#inmymodule.py
print("Thisrunsduringimport!")
#Inanotherscript
importmymodule
#Prints:Thisrunsduringimport!
DEC-MAR 2025 Dr. Reshmi. S I BCA B 189

190. BCA
EmbeddedExecution
Pythoncodeisembeddedwithinanothersystem,such
asawebserver,orexecutedviaaframework.
Example:
1.Pythonscriptsembeddedinautomationtools.
2.WebframeworkslikeFlaskorDjangohandling
Pythoncodeexecution.
Command-LineExecution
SpecificcodepasseddirectlytoPythonviathe
commandlineusingthe-coption.
Example:
python-c"print('Hello,World!')"
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191. BCA
ExecutioninFrozenBinaryExecutables
Pythonscriptsareconvertedintoexecutablesusing
toolslikePyInstallerorcx_Freeze.
ThePythoninterpreterisbundledwiththecode.
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REPL(Read-Eval-PrintLoop)Execution
Extensionsoftheinteractivemode,oftenwithadded
features(e.g.,IPythonorJupyterNotebook).
Codeisexecutedinchunks(cells).

192. BCA
AsynchronousandConcurrentExecution
Usingconstructslikeasyncandawaitfor
asynchronoustasks.
Allowsfornon-blockingcodeexecution.
Example:
importasyncio
asyncdefgreet():
print("Hello,AsyncWorld!")
asyncio.run(greet())
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193. BCA
Explanation
importasyncio:
Theasynciomoduleisimported,whichprovidessupportfor
asynchronousprogramminginPython.
asyncdefgreet():
Thisdefinesanasynchronousfunctiongreetusingtheasync
defsyntax.Insidethefunction,itsimplyprints"Hello,Async
World!".
asyncio.run(greet()):
Thisfunctionisusedtorunanasyncco-routine.
Itsetsuptheeventloop,runstheco-routineuntilitcompletes,
andthenclosestheeventloop.
Here,itexecutesthegreetco-routine,whichprintsthe
messagetotheconsole.
DEC-MAR 2025 Dr. Reshmi. S I BCA B 193

194. BCA
DEC-MAR 2025 Dr. Reshmi. S I BCA B
194
Python
implementation
alternatives

195. BCA
Therearefiveprimaryimplementationsofthe
Pythonlanguage:
CPython
Jython
IronPython
Stackless
PyPy
Otherincludesasoptimizationtoolsbecausetheydo
notimplementthestandardPythonlanguage.
Cython
ShedSkinsystems
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196. BCA
Cpython–TheStandard
Definition:
Thedefaultandmostwidelyusedimplementation
ofPython,writteninC.
ItfollowstheofficialPythonspecificationsandis
maintainedbythePythonSoftwareFoundation.
Features:
DirectlyexecutesPythoncodebyinterpretingit
intobytecodeandrunningitontheCPython
VirtualMachine.
SupportsCextensionsforperformance
improvements.
CompatiblewithmostPythonlibraries.
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197. BCA
Jython–PythonforJava
Definition:
APythonimplementationwritteninJavathat
runsontheJavaVirtualMachine(JVM).Itallows
seamlessintegrationbetweenPythonandJava.
Features:
PythoncodecancallJavalibrariesdirectlyand
viceversa.
UsefulforJavadeveloperswhoneedPython
scriptingcapabilities.
LimitedcompatibilitywithCPythonlibraries(e.g.,
Cextensionsarenotsupported).
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198. BCA
IronPython–Pythonfor.NET
Definition:
APythonimplementationwritteninC#thatruns
onthe.NETframeworkandintegrateswith.NET
applications.
Features:
Pythoncodecaninteractwith.NETlibrariesand
applications.
PrimarilyusedinMicrosoftenvironments.
DoesnotsupportsomeCPython-specificlibraries,
suchasthoserelyingonCextensions.
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199. BCA
StacklessPython–Pythonforconcurrency
(managemultipletasksatonce,improvingperformanceandresponsiveness)
Definition:
APythonimplementationthatemphasizes
concurrencybyavoidingtherelianceontheCcall
stack.Itallowstheexecutionoflightweight
microthreads(tasklets).
Features:
Enablesefficientconcurrencywithoutusing
traditionalOSthreads.
Idealforapplicationsrequiringhighperformance
andscalability,likegamesandsimulations.
FullycompatiblewithCPython'slanguage
features.
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200. BCA
PyPy–Pythonforspeed
Definition:
APythonimplementationwithaJust-In-Time
(JIT)compilerdesignedforperformance
optimization.ItiswritteninPython(RPython
subset).
Features:
SignificantlyfasterexecutionformanyPython
programscomparedtoCPython.
CompatiblewithmostPythonlibraries.
Focusedonreducingruntimeoverheadthrough
JITcompilation.
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201. BCA
Cython
Definition:
CythonisasupersetofPythondesignedto
facilitatethedevelopmentofCextensionsfor
Python.ItallowsyoutowritePythoncodewith
optionalstatictyping,whichisthencompiledinto
highlyefficientCcode.
Features:
PerformanceBoost:SpeedsupPythoncodeby
convertingitintoCandenablingdirect
interactionwithC-levellibraries.
StaticTyping:Youcandeclarevariabletypes,
leadingtofurtherperformanceoptimization.
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202. BCA
Features:
Compatibility:Itworksseamlesslywithexisting
Pythoncodebases.
UseCase:Oftenusedincomputationallyintensive
taskssuchasnumericalcomputations,machine
learning,anddatascience.
Example:
#Cythoncodewithstatictyping
defadd(inta,intb):
returna+b
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203. BCA
ShedSkinSystems
Definition:
ShedSkinisanexperimentalPython-to-C++
compilerthattranslatesasubsetofPythoncode
intoC++code.Itfocusesonstatictyping,
convertingPythonprogramsintooptimizedC++
implementations.
Features:
PerformanceOptimization:GeneratesC++code
forfasterexecutionofPythonprograms.
StaticTyping:RequiresPythonprogramsto
adheretotypeconstraints,asitdoesnotsupport
Python’sdynamicfeatures(e.g.,eval,dynamic
typing).
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204. BCA
Features:
SubsetofPython:Onlysupportsastaticallytyped
subsetofPython,whichlimitsitscompatibility
withfullydynamicPythonprograms.
UseCase:Usefulforperformance-critical
applicationsthatcanfitwithinitsstatictyping
constraints.
Example:
#PythoncodecompatiblewithShedSkin
deffib(n):
ifn<=1:
returnn
returnfib(n-1)+fib(n-2)
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205. BCA
BothtoolsaimtoenhancePython's
performance but with differing
approaches:
CythonfocusesonPythonwithC-like
enhancementsandintegration.
ShedSkincompilesPythonintoC++for
speedbutsacrificesPython’sdynamic
nature.
DEC-MAR 2025 Dr. Reshmi. S I BCA B 205

206. BCA
DEC-MAR 2025
Dr. Reshmi. S I BCA B 206
DEPARTMENTOFCOMPUTERSCIENCE&APPLICATIONS