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FIRST EDITION

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Sample Paper-4PART - III

25. •Constructorsarefunctionsthatbuildtheabstractdatatype. • Selectorsarefunctionsthatretrieveinformationfromthedatatype. 26. A search algorithm is the step-by-step procedure used to locate specific data among a

collectionofdata.Typesofsearchingalgorithmsare*Linearsearch*Binarysearch*Hashsearch*BinaryTreesearch

27. Python uses the symbols and symbol combinations as delimiters in expressions, lists,dictionariesandstrings.Followingarethedelimiters.

( ) [ ] { }

, : . ‘ = ;

+= -= *= /= //= %=

&= |= ^= >>= <<= **=

28. Aloopplacedwithinanotherloopiscalledasnestedloopstructure.Onecanplaceawhilewithinanotherwhile;forwithinanotherfor;forwithinwhileandwhilewithinfortoconstructsuchnestedloops.

Followingisanexampletoillustratetheuseofforlooptoprintthefollowingpattern 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5

29. n=input("Enteranynumber") sum=0 foriinrange(i,n+1): sum=sum+i print"sum=",sum Output: Enteranynumber5 sum=15

Three-mark & Five-mark Answers for Unsolved Sample Papers

COMPUTER SCIENCE

G-1

G-2 Computer SCienCe – XII

30. sort()functionsortstheelementinlist. Syntax: List.sort(reverse=True/False,Key=myFunc) Bothargumentsareoptional •IfreverseissetasTrue,listsortingisindescendingorder. •Ascendingisdefault. •Key=myFunc;"myFunc"-thenameoftheuserdefinedfunctionthatspecifiesthesorting criteria.

Example MyList=['Thilothamma','Tharani','Anitha','SaiSree','Lavanya'] MyList.sort() print(MyList)

Output: ['Anitha','Lavanya','SaiSree','Tharani','Thilothamma'] 31. SQLcommandwhichcomeunderTransferControlLanguageare: • CommitSavesanytransactionintothedatabasepermanently. • Roll backRestoresthedatabasetolastcommitstate. • Save pointTemporarilysaveatransactionsothatyoucanrollback. 32.

S.No. PYTHON C++

1. Pythonistypicallyan"interpreted"language C++istypicallya"compiled"language

2. Pythonisadynamic-typedlanguage C++iscompiledstaticallytypedlanguage

3. Datatypeisnotrequiredwhiledeclaringvariable

Datatypeisrequiredwhiledeclaringvariable

4. Itcanactbothasscriptingandgeneralpurposelanguage Itisageneralpurposelanguage

33. Pseudo code: 1. Startwiththefirstelement i.e., index=0,comparethecurrentelementwiththenext

elementofthearray. 2. Ifthecurrentelementisgreaterthanthenextelementofthearray,swapthem. 3. Ifthecurrentelementislessthanthenextorrightsideoftheelement,movetothenext

element.GotoStep1andrepeatuntilendoftheindexisreached.

PART - IV 34(a). Rules to be followed to format data in a CSV file

1. Eachrecord(rowofdata)istobelocatedonaseparateline,delimitedbyalinebreakbypressingenterkey.

ANSWERS G-3

Forexample: xxx,yyy denotesenterKeytobepressed

2. Thelastrecordinthefilemayormaynothaveanendinglinebreak. Forexample: ppp,qqq yyy,xxx

3. Theremaybeanoptionalheaderlineappearingasthefirstlineofthefilewiththesameformat as normal record lines.The headerwill contain names corresponding to thefieldsinthefileandshouldcontainthesamenumberoffieldsastherecordsintherestofthefile.

Forexample:field_name1,field_name2,field_name3 aaa,bbb,ccc zzz,yyy,xxxCRLF( Carriage Return and Line Feed) 4. Within the header and each record, there may be one or more fields, separated by

commas.Spacesareconsideredpartofafieldandshouldnotbeignored.Thelastfieldintherecordmustnotbefollowedbyacomma.Forexample:Red,Blue

5. Eachfieldmayormaynotbeenclosedindoublequotes.Iffieldsarenotenclosedwithdoublequotes,thendoublequotesmaynotappearinsidethefields.

Forexample:

"Red","Blue","Green" #Fielddatawithdoublequotes Black,White,Yellow #Fielddatawithoutdoublequotes

6. Fieldscontaininglinebreaks(CRLF),doublequotes,andcommasshouldbeenclosedindouble-quotes.Forexample:

Red,",",BlueCRLF#commaitselfisafieldvalue.Soitisenclosedwithdoublequotes Red,Blue,Green

7. Ifdouble-quotesareusedtoenclosefields,thenadouble-quoteappearinginsideafieldmustbeprecededwithanotherdoublequote.Forexample:

"Red,""Blue","Green",#sincedoublequotesisafieldvalueitisenclosedwith anotherdoublequotes,,White

[OR] (b) importtextwrap text= '"Stringsareimmutable.Sliceisa substringofamainstring.Strideisathirdargumentinslicingoperation"' text_without_Indentation=textwrap.dedent(text) wrapped=textwrap.fill(text_without_Indentation,width=50) print(textwrap.indent(wrapped,'*') print()


Output: • Stringsareimmutable.Sliceisa • substringofamainstring.Stride • isathirdargumentinslicingoperation 35(a) The range( ) is a function used to generate a series of values in Python.Using range( )

function,youcancreatelistwithseriesofvalues.Therange()functionhasthreearguments. Syntax of range ( ) function: range(startvalue,endvalue,stepvalue) where, • startvalue–beginningvalueofseries.Zeroisthedefaultbeginningvalue. • endvalue–upperlimitofseries.Pythontakestheendingvalueasupperlimit–1. • stepvalue– It is anoptional argument,which isused togeneratedifferent intervalof

values. Example : Generatingwholenumbersupto10 forxinrange(1,11): print(x) Output 1 2 3 4 5 6 7 8 9 10

[OR]

(b) (i) Todisplaythedetailsofallemployeesindescendingorderofpay.(ii)Todisplayallemployeeswhoseallowanceisbetween5000and7000.(iii)Toremovetheemployeeswhoaremechanic.(iv)Toaddanewrow.(v) Todisplaythedetailsofallemployeeswhoareoperators.Output:(i) SELECT*FROMemployeeORDERBYDESC;(ii) SELECT*FROMemployeeWHERE((allowance>=5000)AND(allowance<=7000));(iii) DELETEFROMemployeeWHEREdesig="Mechanic";(iv) INSERT INTO employee(Empcode,Name,desig,pay,allowance)VALUES('M1006','RAM','Mechanic',22000,8000);(v) SELECT*FROMemployeeWHEREdesig='operator';

ANSWERS G-5

36(a) Aswelearntinmathematics,thepythonisalsosupportsthesetoperationssuchasUnion,Intersection,differenceandSymmetricdifference.

(i) Union:Itincludesallelementsfromtwoormoresets Inpython,theoperator|isusedtounionoftwosets.Thefunctionunion()isalsousedtojoin

twosetsinpython. Example:ProgramtoJoin(Union)twosetsusingunionoperator set_A={2,4,6,8} set_B={'A','B','C','D'} U_set=set_A|set_B print(U_set) Output: {2,4,6,8,'A','D','C','B'}

(ii) Intersection:Itincludesthecommonelementsintwosets Theoperator&isusedtointersecttwosetsinpython.Thefunctionintersection()isalso

usedtointersecttwosetsinpython. Example:Programtoinsecttwosetsusingintersectionoperator set_A={'A',2,4,'D'} set_B={'A','B','C','D'} print(set_A&set_B) Output: {'A','D'}

(iii) Difference:Itincludesallelementsthatareinfirstset(saysetA)butnotinthesecondset(saysetB)

Theminus(–)operatorisusedtodifferencesetoperationinpython. Thefunctiondifference()isalsousedtodifferenceoperation. Example:Programtodifferenceoftwosetsusingminusoperator set_A={'A',2,4,'D'} set_B={'A','B','C','D'} print(set_A-set_B) Output: {2,4}

(iv) Symmetric difference:Itincludesalltheelementsthatareintwosets (saysetsAandB)butnottheonethatarecommontotwosets.

Thecaret(^)operatorisusedtosymmetricdifferencesetoperationinpython.Thefunctionsymmetric_difference()isalsousedtodothesameoperation.

Example: Program to symmetric difference of two sets usingcaretoperator

set_A={'A',2,4,'D'} set_B={'A','B','C','D'} print(set_A^set_B)

Set A Set B

Set A Set B

Set A Set B

Set A Set B


Output: {2,4,'B','C'}

[OR] (b) defrem_vowels(s): temp_str=" foriins: ifiin"aAeEiIoOuU": pass else: temp_str+=i print("Thestringwithoutvowels:",temp_str) str1=input("EnteraString:") rem_vowels(str1) Output: EnteraString:MathematicalfoundationsofComputerScience Thestringwithoutvowels:MthmtclfndtnsfCmptrScnc 37(a) Thefetchall()methodisusedtofetchallrowsfromthedatabasetable importsqlite3 connection=sqlite3.connect("Academy.db") cursor=connection.cursor() cursor.execute("SELECT*FROMstudent") print("fetchall:") result=cursor.fetchall() forrinresult: print(r) Output: fetchall: (1,'Akshay','B','M',87.8,'2001-12-12') (2,'Aravind','A','M',92.5,'2000-08-17') (3,'BASKAR','C','M',75.2,'1998-05-17') (4,'SAJINI','A','F',95.6,'2002-11-01') (5,'VARUN','B','M,80.6,'2001-03-14') (6,'PRIYA','A','F',98.6,'2002-01-01') (7,'TARUN','D','M',62.3,'1999-02-01')

[OR] (b) #include<iostream> usingnamespacestd; //Functiondeclaration intcube(intnum); intmain()

ANSWERS G-7

{ intnum; intc; cout<<"Enteranynumber:"<<endl; cin>>num; c=cube(num); cout<<"Cubeof"<<num<<"is"<<c; return0; } //Functiontofindcubeofanynumber intcube(intnum) { return(num*num*num); } //Savethisfileascube_file.cpp #NowselectFile→NewinNotepadandtypethePythonprogram #SavetheFileasfun.py #Programthatcompilesandexecutesa.cppfile #Pythonfun.py-ic:\pyprg\cube_file.cpp importsys,os,getopt defmain(argv): cpp_file=" exe_file=" opts,args=getopt.getopt(argv,"i:",['ifile=']) foro,ainopts: ifoin("-i","--ifile"): cpp_file=a+'.cpp' exe_file=a+'.exe' run(cpp_file,exe_file) defrun(cpp_file,exe_file): print("Compiling"+cpp_file) os.system('g++'+cpp_file+'-o'+exe_file) print("Running"+exe_file) print("-------------------") print os.system(exe_file) print if__name__=='__main__': main(sys.argv[1:])


Output of the above program Compilingc:\pyprg\cube_file.cpp Runningc:\pyprg\cube_file.exe ------------------- Enteranynumber: 5 Cubeof5is125 38(a) Pythonenablesreverseornegativeindexingforthelistelements.Thus,pythonlistsindexin

oppositeorder.Thepythonsets-1astheindexvalueforthelastelementinlistand-2fortheprecedingelementandsoon.ThisiscalledasReverseIndexing.

Example: Marks=[10,23,41,75] i=–1 whilei>=–4: print(Marks[i]) i=i+–1 Output 75 41 23 10

[OR]

(b) Sorts the element in list Bothargumentsareoptional • IfreverseissetasTrue,listsortingisindescendingorder. • Ascendingisdefault. • Key=myFunc;"myFunc"-thenameoftheuserdefinedfunctionthatspecifiesthesorting

criteria. MyList=['Thilothamma','Tharani','Anitha', 'SaiSree','Lavanya'] MyList.sort() print(MyList) MyList.sort(reverse=True) print(MyList) Output: ['Anitha','Lavanya','SaiSree','Tharani','Thilothamma'] ['Thilothamma','Tharani','SaiSree','Lavanya','Anitha']

ANSWERS G-9


25. 1. Input - Zeroormorequantitiestobesupplied.2. Output - Atleastonequantityisproduced.3. Finiteness - Algorithmsmustterminateafterfinitenumberofsteps.4. Definiteness - All operations should be well defined. For example operations

involvingdivisionbyzeroortakingsquarerootfornegativenumberareunacceptable.

5. Effectiveness - Everyinstructionmustbecarriedouteffectively.6. Correctness - Thealgorithmsshouldbeerrorfree.7. Simplicity - Easytoimplement.8. Unambiguous - Algorithmshouldbeclearandunambiguous.Eachofitsstepsandtheir

inputs/outputsshouldbeclearandmustleadtoonlyonemeaning.9. Feasibility - Shouldbefeasiblewiththeavailableresources.10. Portable - An algorithm should be generic, independent of any programming

languageoranoperatingsystemabletohandleallrangeofinputs.11. Independent - An algorithm should have step-by-step directions,which should be

independentofanyprogrammingcode. 26. CSV File cannot store charts or graphs. It stores data but does not contain formatting,

formulas,macros,etc. ACSVfile isalsoknownasaFlatFile.Files in theCSVformatcanbeimportedtoand

exportedfromprogramsthatstoredataintables,suchasMicrosoftExcelorOpenOfficeCalc. 27. SAVEPOINT command

TheSAVEPOINTcommandisusedtotemporarilysaveatransactionsothatyoucanrollbacktothepointwheneverrequired.ThedifferentstatesofourtablecanbesavedatanytimeusingdifferentnamesandtherollbacktothatstatecanbedoneusingtheROLLBACKcommand.SAVEPOINT savepoint_name;UPDATE Student SET Name = 'Mini' WHERE Admno=105;SAVEPOINT A;

28. DISTINCT KeywordTheDISTINCTkeywordisusedalongwiththeSELECTcommandtoeliminateduplicaterowsinthetable.Thishelpstoeliminateredundantdata.ForExample:SELECT DISTINCT Place FROM Student;Willdisplaythefollowingdataasfollows:SELECT * FROM Student;OutputPlaceChennaiBangaloreDelhi


29. x=0 #globalvariable defadd(): globalx x=x+5 #incrementby2 print("Insideadd()functionxvalueis:",x) add() print("Inmainxvalueis:",x) Output: Insideadd()functionxvalueis:5 Inmainxvalueis:530. •Lambdafunctionismostlyusedforcreatingsmallandone-timeanonymousfunction. • Lambdafunctionsaremainlyusedincombinationwiththefunctionslikefilter(),map()

andreduce(). 31. (i)Toautomatecertaintasksinaprogram.

(ii)Extractinginformationfromadataset. (iii)Lesscodeintensiveascomparedtotraditionalprogramminglanguage. 32. #Programtojointwotuples Tup1=(2,4,6,8,10) Tup2=(1,3,5,7,9) Tup3=Tup1+Tup2 print(Tup3) Output (2,4,6,8,10,1,3,5,7,9) 33. Output: 246810

PART - III

34(a) Excel CSV

1. Excelisabinaryfilethatholdsinformationaboutalltheworksheetsinafile,includingbothcontentandformatting.

CSVformatisaplaintextformatwithaseriesofvaluesseparatedbycommas.

2. XLSfilescanonlybereadbyapplicationsthathavebeenespeciallywrittentoreadtheirformat,andcanonlybewritteninthesameway.

CSVcanbeopenedwithanytexteditorinWindowslikenotepad,MSExcel,OpenOffice,etc.

3. Excelisaspreadsheetthatsavesfilesintoitsownproprietaryformatviz.xlsorxlsx.

CSVisaformatforsavingtabularinformationintoadelimitedtextfilewithextension.csv

4. Excelconsumesmorememorywhileimportingdata.

ImportingCSVfilescanbemuchfaster,anditalsoconsumeslessmemory.

ANSWERS G-11

[OR] (b) ThesyntaxtoexecutethePythonprogramis

Python <filename.py> -i <C++ filename without cpp extension>Where,Python keywordtoexecutethePythonprogramfromcommandlinefilename.py NameofthePythonprogramtoexecuted-i inputmodeC++filenamewithout nameofC++filetobecompiledandexecutedcppextensionForexampletypePythonpycpp.py-ipaliinthecommandpromptandpressenterkey.Ifthecompilationissuccessfulyouwillgetthedesiredoutput.Otherwisetheerrorwillbedisplayed.

35(a) MyList=[1,3,5,7,9] print("ListOddnumbers...") forxinMyList: print(x) MyList[0:5]=2,4,6,8,10 print("ListEvennumbers...") foryinMyList: print(y) Output ListOddnumbers... 1 3 5 7 9 ListEvennumbers... 2 4 6 8 10

[OR]

(b) The range( ) is a functionused togenerate a seriesofvalues inPython.Using range ( )function,youcancreatelistwithseriesofvalues.Therange()functionhasthreearguments.

Syntax of range ( ) function: range (start value, end value, step value) where,

• startvalue–beginningvalueofseries.Zeroisthedefaultbeginningvalue. • endvalue–upperlimitofseries.Pythontakestheendingvalueasupperlimit–1.


• stepvalue–Itisanoptionalargument,whichisusedtogeneratedifferentintervalofvalues.

Example : Generating whole numbers upto 10 forxinrange(1,11): print(x) Output 1 2 3 4 5 6 7 8 9 10 36(a) 1.(12,78,91,"Tamil","Telugu",3.14,69.48)

2. (91,"Tamil","Telugu") 3. (12,78,91,"Tamil","Telugu") 4. ("Telugu",3.14,69.48) 5. (12,78,91,"Tamil","Telugu",3.14,69.48)

[OR] (b) (2,4,6,8,10) NameError:name"T"notdefined. 37(a)

Algorithm Program1. Algorithmhelpstosolveagivenproblem

logicallyanditcanbecontrastedwiththeprogram.

Programisanexpressionofalgorithminaprogramminglanguage.

2. Algorithmcanbecategorizedbasedontheirimplementationmethods,designtechniquesetc.

Algorithmcanbeimplementedbystructuredorobjectorientedprogrammingapproach.

3. Thereisnospecificrulesforalgorithmwritingbutsomeguidelinesshouldbefollowed.

Programshouldbewrittenfortheselectedlanguagewithspecificsyntax.

4. Algorithmresemblesapseudocodewhichcanbeimplementedinanylanguage.

Programismorespecifictoaprogramminglanguage.

[OR] (b) • Input:Zeroormorequantitiestobesupplied. • Output:Atleastonequantityisproduced. • Finiteness:Algorithmsmustterminateafterfinitenumberofsteps.

ANSWERS G-13

• Definiteness:Alloperationsshouldbewelldefined.Forexampleoperationsinvolvingdivisionbyzeroortakingsquarerootfornegativenumberareunacceptable.

• Effectiveness:Everyinstructionmustbecarriedouteffectively. • Correctness:Thealgorithmsshouldbeerrorfree. • Simplicity:Easytoimplement. • Unambiguous:Algorithmshouldbeclearandunambiguous.Eachofitsstepsandtheir

inputs/outputsshouldbeclearandmustleadtoonlyonemeaning. • Feasibility:Shouldbefeasiblewiththeavailableresources. • Portable:Analgorithmshouldbegeneric,independentofanyprogramminglanguageor

anoperatingsystemabletohandleallrangeofinputs. • Independent: An algorithm should have step-by-step directions, which should be

independentofanyprogrammingcode. 38(a) Literalisarawdatagiveninavariableorconstant.InPython,therearevarioustypesof

literals. (i)Numeric (ii)String (iii)Boolean

(i) Numeric Literals:NumericLiteralsconsistsofdigitsandareimmutable(unchangeable).Numericliteralscanbelongto3differentnumericaltypesInteger,FloatandComplex.

To demonstrate Numeric literals#ProgramtodemonstrateNumericLiterals a=0b1010 #BinaryLiterals b=100 #DecimalLiteral c=0o310 #OctalLiteral d=0x12c #HexadecimalLiteral print("IntegerLiterals:",a,b,c,d) #FloatLiteral float_1=10.5 float_2=1.5e2 print("FloatLiterals:",float_1,float_2) #ComplexLiteral x=1+3.14j print("ComplexLiterals:",x) Print("x=",x,"Imaginarypartofx=",x.imag,"Realpartofx=",x.real) #EndoftheProgram Output: IntegerLiterals:10100200300 FloatLiterals:10.5150.0 ComplexLiterals: x=(1.3.14)Imaginarypartofx=3.14Realpartof9x=1.0 (ii) String Literals:InPythonastringliteralisasequenceofcharacterssurroundedby

quotes.Pythonsupportssingle,doubleandtriplequotesforastring.Acharacterliteralisasinglecharactersurroundedbysingleordoublequotes.Thevaluewithtriple-quote"''"isusedtogivemultilinestringliteral.

(iii) Boolean Literals:ABooleanliteralcanhaveanyofthetwovalues:TrueorFalse. (iv) Escape Sequences: InPython strings, thebackslash "\" is a special character, also


calledthe"escape"character.Itisusedinrepresentingcertainwhitespacecharacters:"\t" isa tab,"\n" isanewline,and"\r" isacarriagereturn.Forexampletoprint themessage"It’sraining",thePythoncommandis

>>>print("It\’srainning") It’srainning Pythonsupportsthefollowingescapesequencecharacters.

Escape sequencecharacter Description Example Output

\\ Backslash >>>print("\\test") \test\’ Single-quote >>>print("Doesn\'t") Doesn't

[OR] (b) Tokens

PythonbreakseachlogicallineintoasequenceofelementarylexicalcomponentsknownasTokens. Thenormaltokentypesare (i)Identifiers (ii)Keywords (iii)Operators (iv)Delimiters (v)Literals.Whitespaceseparationisnecessarybetweentokens,identifiersorkeywords.(i) IdentifiersAnIdentifierisanameusedtoidentifyavariable,function,class,moduleorobject.•Anidentifiermuststartwithanalphabet(A..Zora..z)orunderscore(_).•Identifiersmaycontaindigits(0..9)•Pythonidentifiersarecasesensitivei.e.uppercaseandlowercaselettersaredistinct.•Identifiersmustnotbeapythonkeyword.•Pythondoesnotallowpunctuationcharactersuchas%,$,@etc.,withinidentifiers.Example of valid identifiers Sum,total_marks,regno,num1Example of invalid identifiers 12Name,name$,total-mark,continue(ii) KeywordsKeywordsarespecialwordsusedbyPythoninterpretertorecognizethestructureofprogram.Asthesewordshavespecificmeaningforinterpreter,theycannotbeusedforanyotherpurpose.

Python’sKeywordsfalse class finally is returnnone continue for lambda trytrue def from nonlocal whileand del global not withas elif If or yieldassert else import passbreak except In raise

ANSWERS G-15

(iii) OperatorsIn computer programming languages operators are special symbolswhich representcomputations,conditionalmatchingetc.Thevalueofanoperatorusediscalledoperands. Operators are categorized asArithmetic,Relational,Logical,Assignment etc.Value andvariableswhenusedwithoperatorareknownasoperands.Arithmetic operatorsAnarithmeticoperatorisamathematicaloperatorthattakestwooperandsandperformsacalculationonthem.Theyareusedforsimplearithmetic.Mostcomputerlanguagescontainasetofsuchoperatorsthatcanbeusedwithinequationstoperformdifferenttypesofsequentialcalculations.PythonsupportsthefollowingArithmeticoperators.

Operator - Operation Examples ResultAssumea=100andb=10.Evaluatethefollowingexpressions+(Addition) >>>a+b 110-(Subtraction) >>>a–b 90*(Multiplication) >>>a*b 1000/(Divisioin) >>>a/b 10.0%(Modulus) >>>a%30 10**(Exponent) >>>a**2 10000//(FloorDivision) >>>a//30(IntegerDivision) 3

Relational or Comparative operatorsARelationaloperatorisalsocalledasComparative operatorwhichcheckstherelationshipbetweentwooperands.Iftherelationistrue,itreturnsTrue;otherwiseitreturnsFalse.

Operator - Operation Examples ResultAssumethevalueofa=100andb=35.Evaluatethefollowingexpressions.==(isEqual) >>>a==b False>(Greaterthan) >>>a>b True<(Lessthan) >>>a<b False>=(GreaterthanorEqualto) >>>a>=b True<=(LessthanorEqualto) >>>a<=b False!=(Notequalto) >>>a!=b True

Logical operatorsInpython,Logicaloperatorsareusedtoperformlogicaloperationsonthegivenrelationalexpressions.Therearethreelogicaloperatorstheyareand, or andnot.

Operator Example ResultAssumea=97andb=35,EvaluatethefollowingLogicalexpressionsor >>>a>bora==b Trueand >>>a>banda==b Falsenot >>>nota>b False(i.e.)NotTrue


Assignment operatorsInPython,=isasimpleassignmentoperatortoassignvaluestovariable.Leta=5andb=10assignsthevalue5toaand10tobthesetwoassignmentstatementcanalsobegivenasa,b=5,10thatassignsthevalue5and10ontherighttothevariablesaandbrespectively.TherearevariouscompoundoperatorsinPythonlike+=,-=,*=,/=,%=,**=and//=arealsoavailable.

Operator Description ExampleAssumex=10= Assignsrightsideoperandstoleftvariable >>>x=10

>>>b="Computer"+= Addedandassignbacktheresulttoleftoperandi.e.

x=30>>>x+=20#x=x+20

–= Subtractedandassignbacktheresulttoleftoperandi.e.x=25

>>>x–=5#x=x–5

*= Multipliedandassignbacktheresulttoleftoperandi.e.x=125

>>>x*=5#x=x*5

/= Dividedandassignbacktheresulttoleftoperandi.e.x=62.5

>>>x/=2#x=x/2

%= Takenmodulus(Remainder)using twooperandsandassigntheresulttoleftoperandi.e.x=2.5

>>>x%=3#x=x%3

**= Performedexponential(power)calculationonoperatorsandassignvaluetotheleftoperandi.e.x=6.25

>>>x**=2#x=x**2

//= Performed floor division on operators and assignvaluetotheleftoperandi.e.x=2.0

>>>x//=3

Conditional operatorTernaryoperatorisalsoknownasconditionaloperatorthatevaluatesomethingbasedonaconditionbeingtrueorfalse.Itsimplyallowstestingaconditioninasinglelinereplacingthemultilineif-elsemakingthecodecompact.TheSyntaxconditionaloperatoris, Variable Name = [on_true] if [Test expression] else [on_false] Example : min=50if49<50else70#min=50 min=50if49>50else70#min=70(iv) DelimitersPython uses the symbols and symbol combinations as delimiters in expressions, lists,dictionariesandstrings.Followingarethedelimiters.

( ) [ ] { }, : . ' = ;+= –= *= /= //= %=&= |= ^= >>= <<= **=

ANSWERS G-17

(v) LiteralsLiteralisarawdatagiveninavariableorconstant.InPython,therearevarioustypesofliterals. (i)Numeric (ii)String (iii)BooleanNumeric LiteralsNumericLiteralsconsistsofdigitsandareimmutable(unchangeable).Numericliteralscanbelongto3differentnumericaltypesInteger,FloatandComplex.String LiteralsInPythonastringliteralisasequenceofcharacterssurroundedbyquotes.Pythonsupportssingle,doubleandtriplequotesforastring.Acharacterliteralisasinglecharactersurroundedbysingleordoublequotes.Thevaluewithtriple-quote'"'"isusedtogivemulti-linestringliteral.Boolean LiteralsABooleanliteralcanhaveanyofthetwovalues:TrueorFalse.Escape SequencesInPythonstrings,thebackslash"\"isaspecialcharacter,alsocalledthe"escape"character.Itisusedinrepresentingcertainwhitespacecharacters:"\t"isatab,"\n"isanewline,and"\r"isacarriagereturn.Forexampletoprintthemessage"It’sraining",thePythoncommandis >>> print ("It\’s rainning") It’s rainningPythonsupportsthefollowingescapesequencecharacters.

Escape sequence character

Description Example Output

\\ Backslash >>>print("\\test") \test\' Single-quote >>>print("Doesn\'t") Doesn't\" Double-quote >>>print("\"Python\"") "Python"\n Newline print("Python","\n","Lang..") PythonLang..\t Tab print("Python","\t","Lang..") PythonLang..


25. num1=int(input("Enterfirstnumber:")) num2=int(input("Entersecondnumber:")) num3=int(input("Enterthirdnumber:")) if(num1<num2)and(num1<num3): smallest=num1 elif(num2<num1)and(num2<num3): smallest=num2 else: smallest=num3 print("Thesmallestnumberis",smallest) Output: Enterfirstnumber:12


Entersecondnumber:7 Enterthirdnumber:15 Thesmallestnumberis7 26. output:

weoo1 27. (i)Functionshelpustodivideaprogramintomodules.Thismakesthecodeeasierto manage.

(ii) Itimplementscodereuse.Everytimeyouneedtoexecuteasequenceofstatements,allyouneedtodoistocallthefunction.

(iii) Functions, allows us to change functionality easily, and different programmers canworkondifferentfunctions.

28. Program:str1="COMPUTER"index=len(str1)foriinstr1: print(str1[:index])

index–=1 29. InPython,append()functionisusedtoaddasingleelementandextend()functionisused

toaddmorethanoneelementtoanexistinglist. Syntax: List.append(elementtobeadded) List.extend([elementstobeadded]) 30. Inthebelowexample,Mylistcontainsanotherlistasanelement.Thistypeoflistisknown

as"NestedList". Nestedlistisalistcontaininganotherlistasanelement. Example:Mylist=["Welcome",3.14,10,[2,4,6]] 31. Listisconstructedbyplacingexpressionswithinsquarebracketsseparatedbycommas.Such

anexpressioniscalledalistliteral.Listcanstoremultiplevalues.Eachvaluecanbeofanytypeandcanevenbeanotherlist.

ExampleforListis[10,20]. Representing Rational Numbers Using List Youcannowrepresentarationalnumberasapairoftwointegersinpseudocode:anumerator

andadenominator. rational(n,d): return[n,d] numer(x): returnx[0] denom(x): returnx[1] 32. Local Scope

Localscopereferstovariablesdefinedincurrentfunction.Always,afunctionwillfirstlookupforavariablenameinitslocalscope.Onlyifitdoesnotfinditthere,theouterscopesarechecked.

ANSWERS G-19

Lookatthisexample1. Disp():

2. a:=7

3. printa

4.Disp()

Entireprogram OutputoftheProgram

Disp():a:=7printa

Disp()

7

Onexecutionoftheabovecodethevariableadisplaysthevalue7,becauseitisdefinedandavailableinthelocalscope.

33. • false • none • true • and • as • assert

PART - IV 34(a) (i)Startwiththemiddleelement: • Ifthesearchelementisequaltothemiddleelementofthearrayi.e.,themiddlevalue

=numberofelementsinarray/2,thenreturntheindexofthemiddleelement. • Ifnot,thencomparethemiddleelementwiththesearchvalue, • Ifthesearchelementisgreaterthanthenumberinthemiddleindex,thenselectthe

elementstotherightsideofthemiddleindex,andgotoStep-1. • If the search element is less than the number in themiddle index, then select the

elementstotheleftsideofthemiddleindex,andstartwithStep-1. (ii) Whenamatchisfound,displaysuccessmessagewiththeindexoftheelementmatched. (iii) Ifnomatchisfoundforallcomparisons,thendisplayunsuccessfulmessage.

[OR]

(b) Step1−Ifitisthefirstelement,itisalreadysorted. Step2−Picknextelement. Step3−Comparewithallelementsinthesortedsub-list. Step4−Shiftalltheelementsinthesortedsub-listthatisgreaterthanthevaluetobesorted Step5−Insertthevalue Step6−Repeatuntillistissorted 35(a) input() function: InPython,input()functionisusedtoacceptdataasinputatruntime.Thesyntaxforinput()

functionis,Variable = input ("prompt string")


Where,promptstringinthesyntaxisastatementormessagetotheuser,toknowwhatinputcanbegiven.

Ifapromptstringisused,itisdisplayedonthemonitor;theusercanprovideexpecteddatafromtheinputdevice.Theinput() takeswhatever is typedfromthekeyboardandstorestheentereddatainthegivenvariable.Ifpromptstringisnotgivenininput()nomessageisdisplayedonthescreen,thus,theuserwillnotknowwhatistobetypedasinput.

Example: input( ) with prompt string >>>city=input("EnterYourCity:") EnterYourCity:Madurai >>>print("Iamfrom",city) IamfromMadurai Example: input( ) without prompt string >>>city=input() Rajarajan >>>print("Iamfrom",city) IamfromRajarajan Notethatinexample-2,theinput( )isnothavinganypromptstring,thustheuserwillnot

knowwhatistobetypedasinput.Iftheuserinputsirrelevantdataasgivenintheaboveexample,thentheoutputwillbeunexpected.So,tomakeyourprogrammoreinteractive,providepromptstringwithinput( ).

The input ( )acceptsalldataasstringorcharactersbutnotasnumbers.Ifanumericalvalueisentered,theinputvaluesshouldbeexplicitlyconvertedintonumericdatatype.Theint ( )functionisusedtoconvertstringdataasintegerdataexplicitly.Wewilllearnaboutmoresuchfunctionsinlaterchapters.

Example : x=int(input("EnterNumber1:")) y=int(input("EnterNumber2:")) print("Thesum=",x+y) Output: EnterNumber1:34 EnterNumber2:56 Thesum=90 Example : Alternate method for the above program x,y=int(input("EnterNumber1:")),int(input("EnterNumber2:")) print("X=",x,"Y=",y) Output: EnterNumber1:30 EnterNumber2:50 X=30Y=50

[OR]

ANSWERS G-21

(b) Components of SQLSQL commands are divided into five categories:

a. Data Definition LanguageTheDataDefinitionLanguage(DDL)consistofSQLstatementsusedtodefinethedatabasestructureorschema.Itsimplydealswithdescriptionsofthedatabaseschemaandisusedtocreateandmodifythestructureofdatabaseobjectsindatabases.SQL commands which comes under Data Definition Language are:

Create Tocreatetablesinthedatabase.Alter Altersthestructureofthedatabase.Drop Deletetablesfromdatabase.Truncate Remove all records from a table, also release the space occupied by those

records.b. Data Manipulation LanguageADataManipulationLanguage(DML)isacomputerprogramminglanguageusedforadding(inserting),removing(deleting),andmodifying(updating)datainadatabase.SQL commands which comes under Data Manipulation Language are :

Insert InsertsdataintoatableUpdate Updatestheexistingdatawithinatable.Delete Deletesallrecordsfromatable,butnotthespaceoccupiedbythem.

c. Data Control Language:ADataControlLanguage(DCL)isusedforcontrollingprivilegesinthedatabase

SQLcommands:GRANT,REVOKEd. Transactional Control Language;Transactionalcontrollanguage(TCL)isusedtomanagetransactionsi.e.changesmadetothedatainthedatabase.SQLcommands:COMMIT,ROLLBACK,SAVEPOINT.

e. Data Query LanguageTheDataQueryLanguage(DQL)havecommandstoqueryorretrievedatafromthedatabase.SQLcommands:SELECT.


36(a) classLibrary: def__init__(self): self.bookname="" self.author=”” defgetdata(self): self.bookname=input("EnterNameoftheBook:") self.author=input("EnterAuthoroftheBook:") defdisplay(self): print("NameoftheBook:",self.bookname) print("AuthoroftheBook:",self.author) print("\n") book=[]#emptylist ch='y' while(ch=='y'): print("1.AddNewBook\n2.DisplayBooks") resp=int(input("Enteryourchoice:")) if(resp==1): L=Library() L.getdata() book.append(L) elif(resp==2): forxinbook: x.display() else: print("Invalidinput....") ch=input("Doyouwantcontinue....") Output: 1.AddNewBook 2.DisplayBooks Enteryourchoice:1 EnterNameoftheBook:ProgramminginC++ EnterAuthoroftheBook:K.Kannan Doyouwantcontinue....y 1.AddNewBook 2.DisplayBooks Enteryourchoice:1 EnterNameoftheBook:LearnPython EnterAuthoroftheBook:V.G.Ramakrishnan Doyouwantcontinue....y 1.AddNewBook 2.DisplayBooks Enteryourchoice:1

ANSWERS G-23

EnterNameoftheBook:AdvancedPython EnterAuthoroftheBook:Dr.Vidhya Doyouwantcontinue....y 1.AddNewBook 2.DisplayBooks Enteryourchoice:1 EnterNameoftheBook:WorkingwithOpenOffice EnterAuthoroftheBook:N.V.Gowrisankar Doyouwantcontinue....y 1.AddNewBook 2.DisplayBooks Enteryourchoice:1 EnterNameoftheBook:DataStructure EnterAuthoroftheBook:K.Lenin Doyouwantcontinue....y 1.AddNewBook 2.DisplayBooks Enteryourchoice:1 EnterNameoftheBook:AnIntroductiontoDatabaseSystem EnterAuthoroftheBook:R.Sreenivasan Doyouwantcontinue....y 1.AddNewBook 2.DisplayBooks Enteryourchoice:2 NameoftheBook:ProgramminginC++ AuthoroftheBook:K.Kannan NameoftheBook:LearnPython AuthoroftheBook:V.G.Ramakrishnan NameoftheBook:AdvancedPython AuthoroftheBook:Dr.Vidhya NameoftheBook:WorkingwithOpenOffice AuthoroftheBook:N.V.Gowrisankar NameoftheBook:DataStructure AuthoroftheBook:K.Lenin NameoftheBook:AnIntroductiontoDatabaseSystem AuthoroftheBook:R.Sreenivasan Doyouwantcontinue....n

[OR] (b) classString: def__init__(self): self.uppercase=0 self.lowercase=0


self.vowels=0 self.consonants=0 self.spaces=0 self.string="" defgetstr(self): self.string=str(input("EnteraString:")) defcount_upper(self): forchinself.string: if(ch.isupper()): self.uppercase+=1 defcount_lower(self): forchinself.string: if(ch.islower()): self.lowercase+=1 defcount_vowels(self): forchinself.string: if(chin('A','a','e','E','i','I','o','O','l','L')): self.vowels+=1 defcount_consonants(self): forchinself.string: if(chnotin('A','a','e','E','i','I','o','O','l','L')): self.consonants+=1 defcount_space(self): forchinself.string: if(ch==""): self.spaces+=1 defexecute(self): self.count_upper() self.count_lower() self.count_vowels() self.count_consonants() self.count_space() defdisplay(self): print("Thegivenstringcontains...") print("%dUppercaseletters"%self.uppercase) print("%dLowercaseletters"%self.lowercase) print("%dVowels"%self.vowels) print("%dConsonants"%self.consonants) print("%dSpaces"%self.spaces) S=String() S.getstr() S.execute()

ANSWERS G-25

S.display() Output: EnteraString:WelcomeToLearnComputerScience Thegivenstringcontains... 5Uppercaseletters 24Lowercaseletters 13Vowels 20Consonants 4Spaces 37(a) ThegetoptmoduleofPythonhelpsyoutoparse(split)command-lineoptionsandarguments.

Thismoduleprovidestwofunctionstoenablecommand-lineargumentparsing. getopt.getopt method Thismethodparsescommand-lineoptionsandparameterlist.Followingisthesyntaxfor

thismethod−<opts>,<args>=getopt.getopt(argv, options, [long_options])

Hereisthedetailoftheparameters− argv− Thisistheargumentlistofvaluestobeparsed(splited).Inourprogramthe

completecommandwillbepassedasalist. options− ThisisstringofoptionlettersthatthePythonprogramrecognizeas,for

inputorforoutput,withoptions(like'i'or'o')thatfollowedbyacolon(:).Herecolonisusedtodenotethemode.

long_options− Thisparameterispassedwithalistofstrings.ArgumentofLongoptionsshould be followedby an equal sign ('='). In our program theC++filenamewill be passed as string and 'i' alsowill be passed alongwith toindicateitastheinputfile.

getopt()methodreturnsvalueconsistingoftwoelements.Eachofthesevaluesarestoredseparatelyintwodifferentlist(arrays)optsandargs.Optscontainslistofsplittedstringslikemode,pathandargscontainsanystringifatallnotsplittedbecauseofwrongpathormode.argswillbeanemptyarrayifthereisnoerrorinsplittingstringsbygetopt().

ForexampleThePythoncodewhichisgoingtoexecutetheC++filep4incommandlinewillhavethegetopt()methodlikethefollowingone.

opts,args=getopt.getopt(argv,"i:",['ifile='])whereoptscontains [('–i','c:\\pyprg\\p4')]–i:– optionnothingbutmodeshouldbefollowedby:'c:\\pyprg\\p4' valuenothingbuttheabsolutepathofC++file.

In our examples since the entire command line commands are parsed and no leftoverargument, the second argument args will be empty []. If args is displayed using print()commanditdisplaystheoutputas[].

>>>print(args) []

[OR] (b) SQLiteisasimplerelationaldatabasesystem,whichsavesitsdatainregulardatafilesor

evenintheinternalmemoryofthecomputer.Itisdesignedtobeembeddedinapplications,


insteadofusinga separatedatabaseserverprogramsuchasMySQLorOracle.SQLite isfast,rigorouslytested,andflexible,makingiteasiertowork.PythonhasanativelibraryforSQLite.TouseSQLite,Step1 importsqlite3Step2 createaconnectionusingconnect()methodandpassthenameofthedatabaseFileStep3 Setthecursorobjectcursor=connection.cursor()

•Connectingtoadatabaseinstep2meanspassingthenameofthedatabasetobeaccessed.Ifthedatabasealreadyexiststheconnectionwillopenthesame.Otherwise,Pythonwillopenanewdatabasefilewiththespecifiedname.

•Cursorinstep3:isacontrolstructureusedtotraverseandfetchtherecordsofthedatabase.•CursorhasamajorroleinworkingwithPython.Allthecommandswillbeexecutedusingcursorobjectonly.

Tocreateatableinthedatabase,createanobjectandwritetheSQLcommandinit. Example:-sql_comm="SQLstatement"

Forexecutingthecommandusethecursormethodandpasstherequiredsqlcommandasaparameter.Manynumberofcommandscanbestoredinthesql_commandcanbeexecutedoneafterother.Anychangesmadeinthevaluesoftherecordshouldbesavedbythecommand"Commit"beforeclosingthe"Tableconnection".

38(a) importsqlite3connectoin=sqlite3.connect("company.db")cursor=connection.cursor()cursor.execute("Select*fromproduct")print("DisplayingRecords")result=cursor.fetchmany(5)print(*result,Sep="\n")Output:Displayingrecords(1003,'Scanner',10500)(1004,'Speaker',3000)(1005,'Printer',8000)(1008,'Monitor',15000)(1010,'Mouse',700)

[OR]

(b) Read a CSV File Using PythonTherearetwowaystoreadaCSVfile.(i)Usethecsvmodule’sreaderfunction(ii)UsetheDictReaderclass.

ANSWERS G-27

Ways to read CSV file

CSV Module’s Reader FunctionYoucanreadthecontentsofCSVfilewiththehelpofcsv.reader()method.Thereaderfunctionisdesignedtotakeeachlineofthefileandmakealistofallcolumns.Then,youjustchoosethecolumnyouwantthevariabledatafor.Usingthismethodonecanreaddatafromcsvfilesofdifferentformatslikequotes(""),pipe(|)andcomma(,).The syntax for csv.reader() is csv.reader(fileobject,delimiter,fmtparams)wherefileobject:- passesthepathandthemodeofthefiledelimiter:- anoptional parametercontaining thestandarddilects like, Ietccanbe

omittedfmtparams: optionalparameterwhichhelptooverridethedefaultvaluesofthedialects

likeskipinitialspace,quotingetc.Canbeomitted

CSV file with default delimiter comma(,)Thefollowingprogramreadafilecalled"samplel.csv"withdefaultdelimitercomma(,)andprintrowbyrow.#importingcsvimportcsv#opening the csv file which is in different location with read modewithopen('c:\\pyprg\\samplel.csv','r')asF:#other way to open the file is f= ( 'c:\\pyprg\\sample 1.csv', 'r') reader=csv.reader(F)#printing each line of the Data row by row


print(row) F.close()OUTPUT ['SNO','NAME','CITY'] ['12101','RAM','CHENNAI'] ['12102','LAVANYA','TIRUCHY'] ['12103','LAKSHMAN','MADURAI']CSV files- data with Spaces at the beginningConsiderthefollowingfile“sample2.csv”containingthefollowingdatawhenopenedthroughnotepad

Topic l Topic 2 Topic 3one two threeExample1 Example2 Example3ThefollowingprogramreadthefilethroughPythonusing“csv.reader()”.importcsvcsv.register_dialect('myDialect',delimiter=',',skipinitialspace=True)F=open('c:\\pyprg\\sample2.csv','r')reader=csv.reader(F,dialect='myDialect’)forrowinreader: print(row)F.close()OUTPUT['Topic1','Topic2','Topic3']['one','two','three']['Example1','Example2','Example3']Asyoucanseein"sample2.csv"therearespacesafterthedelimiterduetowhichtheoutputisalsodisplayedwithspaces.Thesewhitespacescanberemoved,byregisteringnewdialectsusingcsv.register_dialect()classofcsvmodule.Adialectdescribestheformatofthecsvfilethatistoberead.Indialectstheparameterskipinitialspace"isusedforremovingwhitespacesafterthedelimiter.CSV File-Data With QuotesYoucanreadthecsvfilewithquotes,byregisteringnewdialectsusingcsv.register_dialect()classofcsvmodule.Here,wehavequotes.csvfilewithfollowingdata.SNO,Quotes(a)"Thesecrettogettingaheadisgettingstarted."(b)"Excellenceisacontinuousprocessandnotanaccident."(c)"Workharddreambignevergiveupandbelieveyourself."(d)"Failureistheopportunitytobeginagainmoreintelligently."(e)"Thesuccessfulwarrioristheaverageman,withlaser-likefocus."

ANSWERS G-29

ThefollowingProgramread"quotes.csv"file,wheredelimiteriscomma(,)butthequotesarewithinquotes("").importcsvcsv.register_dialect('myDialect',delimiter=',',quoting=csv.QUOTE_ALL,skipinitialspace=True)f=open('c:\\pyprg\\quotes.csv','r')reader=csv.reader(f,dialect='myDialect')forrowinreader: print(row)OUTPUT ['SNO','Quotes'][(a),'Thesecrettogettingaheadisgettingstarted.'][(b),'Excellenceisacontinuousprocessandnotanaccident.'][(c),'Workharddreambignevergiveupandbelieveyourself.'][(d),'Failureistheopportunitytobeginagainmoreintelligently.'][(e),'Thesuccessfulwarrioristheaverageman,withlaser-likefocus.']Intheaboveprogram,registeradialectwithnamemyDialect.Then,weusedcsv. QUOTE_ALL to display all the charactersafterdoublequotes.CSV files with Custom DelimitersYou can read CSV file having custom delimiter by registering a new dialect with the help of csv.register_dialect().Inthefollowingfilecalled"sample4.csv",eachcolumnisseparatedwith|(Pipesymbol)

Roll No Name City12101 Arun Chennai12102 Meena Kovai12103 Ram Nellai103 Ayush M104 Abinandh MThefollowingprogramreadthefile"sample4.csv"withuserdefineddelimiter"|"importcsv csv.register_dialect('myDialect',delimiter='|') withopen('c:\\pyprg\\sample4.csv','r')asf: reader=csv.reader(f,dialect='myDialect') forrowinreader: print(row)f.close()OUTPUT['RollNo','Name','City']['12101','Arun','Chennai']


['12102','Meena','Kovai']['12103','Ram','Nellai']Reading CSV File Into A DictionaryToreadaCSVfileintoadictionarycanbedonebyusingDictReader classofcsvmodulewhichworkssimilartothereader()classbutcreatesanobjectwhichmapsdatatoadictionary.Thekeysaregivenbythefieldnamesasparameter.DictReaderworksbyreadingthefirstlineoftheCSVandusingeachcommaseparatedvalueinthislineasadictionarykey.Thecolumnsineachsubsequentrowthenbehavelikedictionaryvaluesandcanbeaccessedwiththeappropriatekey(i.e.fieldname).IfthefirstrowofyourCSVdoesnotcontainyourcolumnnames,youcanpassafieldnamesparameterintotheDictReader’sconstructortoassignthedictionarykeysmanually.Themaindifferencebetweenthecsv.reader()andDictReader()isinsimpletermscsv.readerand csv.writerworkwith list/tuple,while csv.DictReader and csv.DictWriter workwithdictionary.csv.DictReaderandcsv.DictWritertakeadditionalargumentfieldnamesthatareusedasdictionarykeys.For Example Reading"sample8.csv"fileintoadictionaryimportcsvfilename='c:\\pyprg\\sample8.csv'input_file=csv.DictReader(open(filename;'r'))forrowininput_file: print(dict(row)) #dict() to print dataOUTPUT {'ItemName':'Keyboard','Quantity':'48'} {'ItemName':'Monitor','Quantity':'52'} {'ItemName':'Mouse','Quantity':'20'}Intheaboveprogram,DictReader()isusedtoread"sample8.csv"fileandmapintoadictionary.Then,thefunctiondict()isusedtoprintthedataindictionaryformatwithoutorder.Removethedict()functionfromtheaboveprogramanduseprint(row).Checkyouaregettingthefollowingoutput OrderedDict([('ItemName','Keyboard'),('Quantity','48')]) OrderedDict([('ItemName','Monitor'),('Quantity','52')]) OrderedDict([('ItemName','Mouse'),('Quantity','20')])


25. (a) A Priori estimates:Thisisatheoreticalperformanceanalysisofanalgorithm.Efficiencyofanalgorithmismeasuredbyassumingtheexternalfactors.

(b) A Posteriori testing:Thisiscalledperformancemeasurement.Inthisanalysis,actualstatisticslikerunningtimeandrequiredforthealgorithmexecutionsarecollected.

26. Anarithmeticoperatorisamathematicaloperatorthattakestwooperandsandperformsacalculationonthem.Theyareusedforsimplearithmetic.Mostcomputerlanguagescontaina

ANSWERS G-31

setofsuchoperatorsthatcanbeusedwithinequationstoperformdifferenttypesofsequentialcalculations.

27. InPython,commentsbeginwithhashsymbol(#).Thelinesthatbeginswith#areconsideredas comments and ignoredby thePython interpreter.Commentsmaybe single lineornomulti-lines.Themultilinecommentsshouldbeenclosedwithinasetof#asgivenbelow.

# It is Single line Comment # It is multiline comment which contains more than one line #

28. for each itemin sequence

Yes

No

Body of for

Exit loop

Last itemreached?

29. Output: 12

30. Syntax: Syntax: break continue

Condition

break?

no

Enter loop

false

true

yes

Exit

loop

Remaining body of loop

Test Expression of loop

continue?

no

Enter loop

false

true

yes

Exit

loop

Remaining body of loop

Syntax: pass 31.

String S C H O O LPositivesubscript 0 1 2 3 4 5Negativesubscript –6 –5 –4 –3 –2 –1

32. Syntax: del List [index of an element] #todeleteaparticularelement


del List [index from : index to] #todeletemultipleelements del List #todeleteentirelist 33. Output: Error:SamplehasnoattributeS.___num 10

PART - IV 34(a) Basically,ascriptisatextfilecontainingthePythonstatements.PythonScriptsarereusable

code.Oncethescriptiscreated,itcanbeexecutedagainandagainwithoutretyping.TheScriptsareeditable.

Creating Scripts in Python (i) ChooseFile→NewFileorpressCtrl+NinPythonshellwindow.

(ii) Anuntitledblankscripttexteditorwillbedisplayedonscreen

ANSWERS G-33

(iii) TypethefollowingcodeinScripteditor

a=100 b=350 c=a+b print("TheSum=",c)Saving Python Script(i) ChooseFile→SaveorPressCtrl+S

(ii) Now,SaveAsdialogboxappearsonthescreen

(iii) IntheSaveAsdialogbox,selectthelocationwhereyouwanttosaveyourPythoncode,andtypethefilenameinFileNamebox.Pythonfilesarebydefaultsavedwithextension.py.Thus,whilecreatingPythonscriptsusingPythonScripteditor,noneedtospecifythefileextension.

(iv) Finally,clickSavebuttontosaveyourPythonscript.


Executing Python Script(i) ChooseRun→RunModuleorPressF5

(ii) Ifyourcodehasanyerror,itwillbeshowninredcolorintheIDLEwindow,andPythondescribesthetypeoferroroccurred.Tocorrecttheerrors,gobacktoScripteditor,makecorrections,savethefileusingCtrl+SorFile→Saveandexecuteitagain.

(iii) Forallerrorfreecode,theoutputwillappearintheIDLEwindowofPython

[OR]

(b) Input and Output FunctionsAprogramneedstointeractwiththeusertoaccomplishthedesiredtask;thiscanbeachievedusingInput-Output functions.Theinput()functionhelpstoenterdataatruntimebytheuserandtheoutputfunctionprint()isusedtodisplaytheresultoftheprogramonthescreenafterexecution.The print() functionInPython,theprint()functionisusedtodisplayresultonthescreen.Thesyntaxforprint() isasfollows:Example print("stringtobedisplayedasoutput") print(variable) print("Stringtobedisplayedasoutput",variable) print("String1",variable,"String2",variable,"String3"……)

ANSWERS G-35

Example >>>print("WelcometoPythonProgramming") WelcometoPythonProgramming >>>x=5 >>>y=6 >>>z=x+y >>>print(z) 11 >>>print("Thesum=",z) Thesum=11 >>>print("Thesumof",x,"and",y,"is",z) Thesumof5and6is11Thprint ( )evaluatestheexpressionbeforeprintingitonthemonitor.Theprint()displaysanentirestatementwhichisspecifiedwithinprint().Comma ( , )isusedasaseparatorinprint()toprintmorethanoneitem.input() functionInPython,input( )functionisusedtoacceptdataasinputatruntime.Thesyntaxforinput() functionis, Variable=input("promptstring")Where,prompt stringinthesyntaxisastatementormessagetotheuser,toknowwhatinputcanbegiven.Ifapromptstringisused,itisdisplayedonthemonitor;theusercanprovideexpecteddatafromtheinputdevice.The input( ) takeswhateveris typedfromthekeyboardandstorestheentereddatainthegivenvariable.Ifpromptstringisnotgivenininput( )nomessageisdisplayedonthescreen,thus,theuserwillnotknowwhatistobetypedasinput. Example 1: input( ) with prompt string >>>city=input("EnterYourCity:") EnterYourCity:Madurai >>>print("Iamfrom",city) IamfromMadurai Example 2: input( ) without prompt string >>>city=input() Rajarajan >>>print("Iamfrom",city) IamfromRajarajanNotethatinexample-2,theinput( )isnothavinganypromptstring,thustheuserwillnotknowwhatistobetypedasinput.Iftheuserinputsirrelevantdataasgivenintheaboveexample,thentheoutputwillbeunexpected.So,tomakeyourprogrammoreinteractive,providepromptstringwithinput( ).Theinput ( )acceptsalldataasstringorcharactersbutnotasnumbers.Ifanumericalvalueisentered,theinputvaluesshouldbeexplicitlyconvertedintonumericdatatype.Theint()function


isusedtoconvertstringdataasintegerdataexplicitly.Wewilllearnaboutmoresuchfunctionsinlaterchapters. Example 3: x=int(input("EnterNumber1:")) y=int(input("EnterNumber2:")) print("Thesum=",x+y) Output: EnterNumber1:34 EnterNumber2:56 Thesum=90 Example 4: Alternate method for the above program x,y=int(input("EnterNumber1:")),int(input("EnterNumber2:")) print("X=",x,"Y=",y) Output: EnterNumber1:30 EnterNumber2:50 X=30Y=50

35(a) n=100 sum=0 forcounterinrange(1,n+1): sum=sum+counter print("Sumof1until%d:%d"%(n,sum)) Output: Sumof1until100:5050

[OR]

(b) s1=input("Enterthestringtobereplaced:") s2=input("Enterthestringtoreplacewith") s1=s2 print("Replacedstringis",s1) Output: Enterthestringtobereplaced:Computer Enterthestringtoreplacewith:repcomputer Replacedstringisrepcomputer

36(a) classTr: def__init__(self,a,b,c): self.a=float(a) self.b=float(b) self.c=float(c) defarea(self): s=(self.a+self.b+self.c)/2 return((s*(s-self.a)*(s-self.b)*(s-self.c)**0.5))

ANSWERS G-37

a=input("Enterside1:") b=input("Enterside2:") c=input("Enterside3:") ans=Tr(a,b,c) print(ans.area()) Output: Enterside1:3 Enterside2:4 Enterside3:5 6.0

[OR]

(b) (i) Database Administrator Database Administrator or DBA is the one who manages the complete database

managementsystem.DBAtakescareofthesecurityoftheDBMS,managingthelicensekeys,managinguseraccountsandaccessetc.

(ii) Application Programmers or Software Developers ThisusergroupisinvolvedindevelopinganddesigningthepartsofDBMS. (iii) End User Endusersaretheonewhostore,retrieve,updateanddeletedata. (iv) Database designers:areresponsibleforidentifyingthedatatobestoredinthedatabase

forchoosingappropriatestructurestorepresentandstorethedata. 37(a) TheDatabaseManagementSystemcanbedividedintofivemajorcomponentsasfollows:

(i)Hardware (ii)Software (iii)Data (iv)Procedures/Methods (v)DatabaseAccessLanguages (i) Hardware: The computer, hard disk, I/O

channels for data, and any other physicalcomponentinvolvedinstorageofdata

(ii) Software:Thismain component is a programthat controls everything. The DBMS softwareis capable of understanding the DatabaseAccessLanguagesand interprets intodatabasecommandsforexecution.

(iii) Data: It is that resource for which DBMS isdesigned.DBMScreationistostoreandutilizedata.

(iv) Procedures/Methods: They are generalinstructions to use a database managementsystem such as installation ofDBMS,managedatabases to take backups, report generation,etc.

(v) DataBase Access Languages: They are the languages used to write commands toaccess,insert,updateanddeletedatastoredinanydatabase.

[OR]

Hardware

Data BaseAccessLanguages

DATA

software

USERComponents of DBMS

Procedures/ Methods


(b) IN Keyword TheINkeywordisusedtospecifyalistofvalueswhichmustbematchedwiththerecord

values.Inotherwordsitisusedtocompareacolumnwithmorethanonevalue.ItissimilartoanORcondition.

Forexample: SELECTAdmno,Name,PlaceFROMStudentWHEREPlaceIN("Chennai","Delhi");

Adm No Name Place100 Ashish Chennai101 Adarsh Delhi103 Ayush Delhi104 Abinandh Chennai105 Revathi Chennai107 Hema Chennai

NOT IN: TheNOTINkeyworddisplaysonlythoserecordsthatdonotmatchinthelist. Forexample: SELECTAdmno,Name,PlaceFROMStudentWHEREPlaceNOTIN("Chennai","Delhi"); willdisplaystudentsonlyfromplacesotherthan"Chennai"and"Delhi".

Adm No Name Place102 Akshith Bangalore106 Devika Bangalore

38(a) Mode Description'r' Openafileforreading.(default)'w' Openafileforwriting.Createsanewfileifitdoesnotexistortruncatesthe

fileifitexists.'x' Openafileforexclusivecreation.Ifthefilealreadyexists,theoperationfails.'a' Openforappendingattheendofthefilewithouttruncatingit.Createsanew

fileifitdoesnotexist.'t' Openintextmode.(default)'b' Openinbinarymode.'+' Openafileforupdating(readingandwriting)

[OR]

(b) Python getopt module ThegetoptmoduleofPythonhelpsyoutoparse(split)command-lineoptionsandarguments. Thismoduleprovidestwofunctionstoenablecommand-lineargumentparsing. getopt.getoptmethod Thismethodparsescommand-lineoptionsandparameterlist.Followingisthesyntaxfor

thismethod-

ANSWERS G-39

<opts>,<args>=getopt.getopt( argv, options, {long_options]) Hereisthedetailoftheparameters-

argv- Thisistheargumentlistofvaluestobeparsed(splited).Inourpro-gramthecompletecommandwillbepassedasalist.

options- ThisisstringofoptionlettersthatthePythonprogramrecognizeas,forinputorforoutput,withoptions(like'i'or'o')thatfollowedbyacolon(:).Herecolonisusedtodenotethemode.

long_options- Thisparameterispassedwithalistofstrings.ArgumentofLongoptionsshouldbefollowedbyanequalsign('=').InourprogramtheC++filenamewillbepassedasstringand'i'alsowillbepassedalongwithtoindicateitastheinputfile.

getopt()methodreturnsvalueconsistingoftwoelements.Eachofthesevaluesarestoredseparatelyintwodifferentlist(arrays)optsandargs.Optscontainslistofsplittedstringslikemode,pathandargscontainsanystringifatallnotsplittedbecauseofwrongpathormode.argswillbeanemptyarrayifthereisnoerrorinsplittingstringsbygetopt().ForexampleThePythoncodewhichisgoingtoexecutetheC++filep4incommandlinewillhavethegetopt()methodlikethefollowingone.

opts,args=getopt.getopt(argv,"i:",['ifile='])

whereoptscontains [('-i','c:\\pyprg\\p4')]–i:- optionnothingbutmodeshouldbefollowedby:'c:\\pyprg\\p4' valuenothingbuttheabsolutepathofC++file.Inourexamplessincetheentirecommandlinecommandsareparsedandnoleftoverargument,thesecondargumentargswillbeempty[].Ifargsisdisplayedusingprint()commanditdisplaystheoutputas[].

>>>print(args) [] SomemorecommandforwrappingC++code if__name__=='__main__’; main(sys.argv[1:]) __name__(ASpecialvariable)inPython Sincethereisnomain()functioninPython,whenthecommandtorunaPythonprogram

isgiventotheinterpreter,thecodethatisatlevel0indentationistobeexecuted.However,beforedoingthat,interpreterwilldefineafewspecialvariables._name_isonesuchspecialvariablewhichbydefaultstoresthenameofthefile.Ifthesourcefileisexecutedasthemainprogram,theinterpretersetsthe_name_variabletohaveavalueas"_main_"

__name__isabuilt-invariablewhichevaluatestothenameofthecurrentmodule.Thusitcanbeusedtocheckwhetherthecurrentscriptisbeingrunonitsown.


Forexampleconsiderthefollowing if__name__=='__main__': main(sys.argv[1:]) ifthecommandlinePythonprogramitselfisgoingtoexecutefirst,then_main_contains

thenameofthatPythonprogramandthePythonspecialvariable_name_alsocontainthePythonprogramname.IftheconditionistrueitcallsthemainwhichispassedwithC++fileasargument.


25. InPython,theprint()functionisusedtodisplayresultonthescreen.Thesyntaxforprint()isasfollows:

Example: print("stringtobedisplayedasoutput" ) print(variable) print("Stringtobedisplayedasoutput",variable) print("String1",variable,"String2",variable,"String3"……) 26. AnIdentifierisanameusedtoidentifyavariable,function,class,moduleorobject. • Anidentifiermuststartwithanalphabet(A..Zora..z)orunderscore(_). • Identifiersmaycontaindigits(0..9) • Pythonidentifiersarecasesensitive.i.e.,uppercaseandlowercaselettersaredistinct. • Identifiersmustnotbeapythonkeyword. • Pythondoesnotallowpunctuationcharactersuchas%,$,@etc.,withinidentifiers. 27. Tablesaretheonlywaytostoredata,thereforealltheinformationhastobearrangedinthe

formoftables.TheSQLprovidesapredeterminedsetofcommandstoworkondatabases. Keywords:TheyhaveaspecialmeaninginSQL.Theyareunderstoodasinstructions. Commands:Theyareinstructionsgivenbytheusertothedatabasealsoknownasstatements. Clauses:Theybeginwithakeywordandconsistofkeywordandargument. Arguments:Theyarethevaluesgiventomaketheclausecomplete. 28. Conditional operator

Ternaryoperatorisalsoknownasconditionaloperatorthatevaluatesomethingbasedonaconditionbeingtrueorfalse.Itsimplyallowstestingaconditioninasinglelinereplacingthemultilineif-elsemakingthecodecompact.TheSyntaxconditionaloperatoris, Variable Name = [on_true] if [Test expression] else [on_false] Example : min=50if49<50else70#min=50 min=50if49>50else70#min=70

29. letrecgcdab:= ifb< >0thengcdb(amodb)elsereturna;; output gcd1327;;

ANSWERS G-41

-:int=1 gcd205367826;; -:int=2 Intheaboveexampleprogram'gcd'isthenameofthefunctionwhichrecursivelycalledtill

thevariable'b'becomes'0'.Rememberband(amodb)aretwoargumentspassedto'a'and'b'ofthegcdfunction.

30. SAVEPOINT command TheSAVEPOINTcommandisusedtotemporarilysaveatransactionsothatyoucanrollback

tothepointwheneverrequired.ThedifferentstatesofourtablecanbesavedatanytimeusingdifferentnamesandtherollbacktothatstatecanbedoneusingtheROLLBACKcommand.

SAVEPOINT savepoint_name; UPDATE Student SET Name = 'Mini ' WHERE Admno=105; SAVEPOINT A; 31. Output: Enterastring:welcome Subscript[–1]:e Subscript[–2]:m Subscript[–3]:o Subscript[–4]:c Subscript[–5]:l Subscript[–6]:e Subscript[–7]:w 32. [1,2,4,8,16] 33. Output: Mani 500

PART - IV 34(a) (i) Union:Itincludesallelementsfromtwoormoresets

Inpython,theoperator|isusedtounionoftwosets.Thefunctionunion()isalsousedtojointwosetsinpython.


(ii) Intersection:Itincludesthecommonelementsintwosets

Theoperator&isusedtointersecttwosetsinpython.Thefunctionintersection()isalsousedtointersecttwosetsinpython.(iii) Difference Itincludesallelementsthatareinfirstset(saysetA)butnotinthesecondset(saysetB)

Theminus(–)operatorisusedtodifferencesetoperationinpython.Thefunctiondifference() isalsousedtodifferenceoperation.(iv) Symmetric differenceItincludesalltheelementsthatareintwosets(saysetsAandB)butnottheonethatarecommontotwosets.

ANSWERS G-43


[OR] (b) Inserting elements in a list

append()functioninPythonisusedtoaddmoreelementsinalist.But,itincludeselementsattheendofalist.Ifyouwanttoincludeanelementatyourdesiredposition,youcanuseinsert()functionisusedtoinsertanelementatanypositionofalist.Syntax: List.insert (position index, element)Example>>>MyList=[34,98,47,'Kannan','Gowrisankar','Lenin','Sreenivasan']>>>print(MyList) [34,98,47,'Kannan','Gowrisankar','Lenin','Sreenivasan']>>>MyList.insert(3,'Ramakrishnan')>>>print(MyList)[34,98,47,'Ramakrishnan','Kannan','Gowrisankar','Lenin','Sreenivasan']Intheaboveexample,insert()functioninsertsanewelement'Ramakrishnan'attheindexvalue3,ie.atthe4thposition.Whileinsertinganewelementinbetweentheexistingelements,ataparticularlocation,theexistingelementsshiftsonepositiontotheright.

35(a) 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5i=1while(i<=6): forjinrange(1,i): print(j,end='\t') print(end='\n') i+=1

[OR]

(b) TheALTERcommandisusedtoalter thetablestructurelikeaddingacolumn,renamingtheexistingcolumn,changethedatatypeofanycolumnorsizeofthecolumnordeletethecolumnfromthetable.Itisusedinthefollowingway:

ALTER TABLE <table-name> ADD <column-name> <data type> <size>; Toaddanewcolumn"Address"oftype'char'totheStudenttable,thecommandisusedas

ALTER TABLE Student ADD Address char; To modify existing column of table, theALTER TABLE command can be used with

MODIFYclauselikewise: ALTER <table-name> MODIFY<column-name> <data type> <size>; ALTER TABLE Student MODIFY Address char (25);


TheabovecommandwillmodifytheaddresscolumnoftheStudenttabletonowhold25characters.

TheALTERcommandcanbeusedtorenameanexistingcolumninthefollowingway: ALTER <table-name> RENAME old-column-name TO new-column-name; ForexampletorenamethecolumnAddresstoCity,thecommandisusedas: ALTER TABLE Student RENAME Address TO City; TheALTERcommandcanalsobeusedtoremoveacolumnorallcolumns,forexample

toremoveaparticularcolumn,theDROP COLUMNisusedwiththeALTER TABLEtoremoveaparticularfield,thecommandcanbeusedas:

ALTER <table-name> DROP COLUMN <column-name>; ToremovethecolumnCityfromtheStudenttable,thecommandisusedas: ALTER TABLE Student DROP COLUMN City; 36(a) Output: (i) SELECT*FROMemployeeORDERBYDESC; (ii) SELECT * FROM employee WHERE ((allowance >= 5000) AND (allowance

<=7000)); (iii) DELETEFROMemployeeWHEREdesig="Mechanic"; (iv) INSERTINTOemployee(Empcode,Name,desig,pay,allowance)VALUES('M1006',

'RAM','Mechanic',22000,8000); (v) SELECT*FROMemployeeWHEREdesig='operator';

[OR] (b) AsyouknowPythonprovidesaneasywaytoworkwithCSVfileandhascsvmoduletoread

andwritedatainthecsvfile.Intheprevioustopics,YouhavelearnedhowtoreadCSVfilesinPython.Insimilarway,YoucanalsowriteaneworeditanexistingCSVfilesinPython.

(i) CreatingANewNormalCSVFile (ii) ModifyingAnExistingFile (iii) WritingOnACSVFilewithQuotes (iv) WritingOnACSVFilewithCustomDelimiters (v) WritingOnACSVFilewithLineterminator (vi) WritingOnACSVFilewithQuotechars (vii) WritingCSVFileIntoADictionary (viii)GettingDataAtRuntimeAndWritingInaFile 37(a) classSample: def__init__(self,n1,n2): self.n1=n1 self.__n2=n2 defdisplay(self): print("Classvariable1=",self.n1) print("Classvariable2=",self.__n2) S=Sample(12,14) S.display() print("Value1=",S.n1) print("Value2=",S.__n2) Intheaboveprogram,therearetwoclassvariablesn1andn2aredeclared.Thevariablen1

ANSWERS G-45

isapublicvariableandn2isaprivatevariable.Thedisplay()membermethodisdefinedtoshowthevaluespassedtothesetwovariables.

Theprintstatementsdefinedwithinclasswillsuccessfullydisplaythevaluesofn1andn2,eventhoughtheclassvariablen2isprivate.Because,inthiscase,n2iscalledbyamethoddefinedinsidetheclass.But,whenwetrytoaccessthevalueofn2fromoutsidetheclassPythonthrowsanerror.Because,privatevariablecannotbeaccessedfromoutsidetheclass.

Output: Classvariable1=12 Classvariable2=14 Value1=12 Traceback(mostrecentcalllast): File"D:/Python/Class-Test-04.py",line12,in<module> print("Value2=",S.__n2) AttributeError:'Sample'objecthasnoattribute'__n2'

[OR] (b) Asyouknowatupleisimmutable,theelementsinatuplecannotbechanged.Insteadof

alteringvaluesinatuple,joiningtwotuplesordeletingtheentiretupleispossible. Example: #Programtojointwotuples Tup1=(2,4,6,8,10) Tup2=(1,3,5,7,9) Tup3=Tup1+Tup2 print(Tup3) Output: (2,4,6,8,10,1,3,5,7,9) Todeleteanentiretuple,thedelcommandcanbeused. Syntax: del tuple_name Example: Tup1=(2,4,6,8,10) print("TheelementsofTup1is",Tup1) delTup1 print(Tup1) Output: TheelementsofTup1is(2,4,6,8,10) Traceback(mostrecentcalllast): File"D:/Python/TupleExamp1.py",line4,in<module> print(Tup1) NameError:name'Tup1'isnotdefined Notethat,theprintstatementintheabovecodeprintstheelements.Then,thedelstatement

deletestheentiretuple.Whenyoutrytoprintthedeletedtuple,Pythonshowstheerror. 38(a) Whenweneedtoconstructachainofifstatement(s)then'elif'clausecanbeusedinsteadof

'else'. Syntax: if <condition-1>:


statements-block 1 elif <condition-2>: statements-block 2 else: statements-block n In the syntax of if..elif..else mentioned

above, condition-1 is tested if it is true thenstatements-block1 is executed, otherwisethe control checks condition-2, if it is truestatements-block2 is executed and even if itfailsstatements-blocknmentionedinelsepartisexecuted.

'elif'clausecombinesif..else-if..elsestatementstooneif..elif…else.'elif'canbeconsideredtobeabbreviationof'elseif'.Inan‘if’statementthereisnolimitof'elif'clausethatcanbeused,butan'else'clauseifusedshouldbeplacedattheend.

Example: Program to illustrate the use of nested if statement Average Grade >=80andabove A >=70and<80 B >=60and<70 C >=50and<60 D Otherwise E m1=int(input("Entermarkinfirstsubject:”)) m2=int(input("Entermarkinsecondsubject:")) avg=(m1+m2)/2 ifavg>=80: print("Grade:A") elifavg>=70andavg<80: print("Grade:B") elifavg>=60andavg<70: print("Grade:C") elifavg>=50andavg<60: print("Grade:D") else: print("Grade:E") Output 1: Entermarkinfirstsubject:34 Entermarkinsecondsubject:78 Grade:D

Test Expression

of if

Test Expression

of elifBody of if

Body of elifBody of else

false

false

True

True

if..elif..else statement execution

ANSWERS G-47

Output 2 : Entermarkinfirstsubject:67

[OR]

(b) Parametersorargumentscanbepassedtofunctions def function_name (parameter(s) separated by comma): Letussee theuseofparameterswhiledefiningfunctions.Theparameters thatyouplace

intheparenthesiswillbeusedbythefunctionitself.Youcanpassallsortsofdatatothefunctions.Hereisanexampleprogramthatdefinesafunctionthathelpstopassparametersintothefunction.

#assumew=3andh=5 defarea(w,h): returnw*h print(area(3,5)) The above code assigns the width and height values to the parameters w and h. These

parametersareusedinthecreationofthefunction"area".Whenyoucalltheabovefunction,itreturnstheproductofwidthandheightasoutput.

Thevalueof3and5arepassedtowandhrespectively,thefunctionwillreturn15asoutput.


25. InPython,aclass isdefinedbyusing thekeywordclass.Everyclasshasauniquenamefollowedbyacolon(:).

Syntax: class class_name: statement_1 statement_2 ………….. ………….. statement_n Where,statementinaclassdefinitionmaybeavariabledeclaration,decisioncontrol,loop

orevenafunctiondefinition.Variablesdefinedinsideaclassarecalledas"ClassVariable"andfunctionsarecalledas"Methods".Classvariableandmethodsaretogetherknownasmembersoftheclass.Theclassmembersshouldbeaccessedthroughobjectsorinstanceofclass.AclasscanbedefinedanywhereinaPythonprogram.

Example:Programtodefineaclass classSample: x,y=10,20 # class variables Intheabovecode,nameoftheclassisSampleandithastwovariablesxandyhavingthe

initialvalue10and20respectively.Toaccessthevaluesdefinedinsidetheclass,youneedanobjectorinstanceoftheclass.


26. ThebasicrulesforglobalkeywordinPythonare:•Whenwedefineavariableoutsideafunction,it’sglobalbydefault.Youdon’thavetouseglobalkeyword.

•Weuseglobalkeywordtoreadandwriteaglobalvariableinsideafunction.•Useofglobalkeywordoutsideafunctionhasnoeffect.

27. SAVEPOINT command TheSAVEPOINTcommandisusedtotemporarilysaveatransactionsothatyoucanrollback

tothepointwheneverrequired.ThedifferentstatesofourtablecanbesavedatanytimeusingdifferentnamesandtherollbacktothatstatecanbedoneusingtheROLLBACKcommand.

SAVEPOINT savepoint_name; UPDATE Student SET Name = 'Mini ' WHERE Admno=105; SAVEPOINT A; 28. Example: importsqlite3 connection=sqlite3.connect("Academy.db") cursor=connection.cursor() cursor.execute("SELECTgender,count(gender)FROMstudentGroupBYgender") result=cursor.fetchall() print(*result,sep="\n") Output: ('F',2) ('M',5) 29. Output: weoo130.

( ) [ ] { }, : . ' = ;

+= –= *= /= //= %=&= |= ^= >>= <<= **=

31. InPythonastringliteralisasequenceofcharacterssurroundedbyquotes.Pythonsupportssingle,doubleandtriplequotesforastring.Acharacterliteralisasinglecharactersurroundedbysingleordoublequotes.Thevaluewithtriple-quote"' '"isusedtogivemulti-linestringliteral.

strings="ThisisPython" char="C" multiline_str="'Thisisamultilinestringwithmorethanonelinecode."' 32. #Programtodemonstrateconditionaloperator a,b=30,20 #Copyvalueofainminifa<belsecopyb min=aifa<belseb print("TheMinimumofAandBis",min)

ANSWERS G-49

#EndoftheProgram Output: TheMinimumofAandBis2033. •Functionblocksbeginwiththekeyword"def"followedbyfunctionnameand

parenthesis().•Anyinputparametersorargumentsshouldbeplacedwithintheseparentheseswhenyoudefineafunction.•Thecodeblockalwayscomesafteracolon(:)andisindented.•Thestatement"return[expression]"exitsafunction,optionallypassingbackanexpressiontothecaller.A"return"withnoargumentsisthesameasreturnNone.

PART - IV 34(a)

Question AnswerTo test Logical Operators:Example - Code Output#Demo Program to test Logical Operatorsa=int (input("Enter a Value for A:"))b=int (input("Enter a Value for B:"))print ("A = ",a, " and b = ",b)print ("The a > b or a == b = ",a>b or a==b)print ("The a > b or a == b = ",a>b and a==b)print ("The not a > b ",not a>b)#Program End

EnteraValueforA:50EnteraValueforB:40A=50andb=40Thea>bora==b=TrueThea>banda==b=FalseThenota>b=False

[OR]

(b) Example: #Program to check if the accepted number odd or even a=int(input("Enteranynumber:")) ifa%2==0: print(a,"isanevennumber") else: print(a,"isanoddnumber") Output 1: Enteranynumber:56 56isanevennumber Output 2: Enteranynumber:67 67isanoddnumber 35(a) Syntax: while <condition>: statements block 1


[else: statements block 2] Inthewhileloop,theconditionisanyvalidBoolean

expression returning True or False. The else partofwhile isoptionalpartofwhile.The statementsblock1 is kept executed till the condition isTrue.If theelsepart iswritten, it is executedwhen theconditionistestedFalse.Recallwhileloopbelongstoentrychecklooptype, that is it isnotexecutedeven once if the condition is tested False in thebeginning.

Example: program to illustrate the use of while loop - to print all numbers from 10 to 15 i=10 #initializing part of the control variable while(i<=15): # test condition print(i,end='\t') # statements - block 1 i=i+1 # Updation of the control variable Output: 101112131415

[OR]

(b) Types of FunctionsBasically,wecandividefunctionsintothefollowingtypes: (i) User-definedFunctions (ii) Built-inFunctions (iii) LambdaFunctions (iv) RecursionFunctions

Functions DescriptionUser-definedfunctions Functionsdefinedbytheusersthemselves.Built-infunctions FunctionsthatareinbuiltwithinPython.Lambdafunctions Functionsthatareanonymousun-namedfunction.Recursionfunctions Functionsthatcallsitselfisknownasrecursive.

(i) Syntax for User defined function def <function_name ([parameter1, parameter2…] )> : <Block of Statements> return <expression / None>Example: defhello(): print("hello-Python") return

Condition

Conditional Code

while Expression: Statement (s)

if conditions is true

if condition is false

ANSWERS G-51

Advantages of User-defined Functions: (i)Functionshelpustodivideaprogramintomodules.Thismakesthecodeeasiertomanage. (ii)Itimplementscodereuse.Everytimeyouneedtoexecuteasequenceofstatements,all

youneedtodoistocallthefunction.(iii)Functions,allowsustochangefunctionalityeasily,anddifferentprogrammerscanwork

ondifferentfunctions.(ii) Anonymous FunctionsInPython,anonymousfunctionisafunctionthatisdefinedwithoutaname.Whilenormalfunctionsaredefinedusing thedef keyword, inPythonanonymousfunctionsaredefinedusingthelambdakeyword.Hence,anonymousfunctionsarealsocalledaslambda functions.The use of lambda or anonymous function:•Lambdafunctionismostlyusedforcreatingsmallandone-timeanonymousfunction.•Lambdafunctionsaremainlyusedincombinationwiththefunctionslikefilter(),map()andreduce().

Syntax of Anonymous FunctionsThesyntaxforanonymousfunctionsisasfollows: lambda [argument(s)] :expressionExample: sum=lambdaarg1,arg2:arg1+arg2 print('TheSumis:',sum(30,40)) print('TheSumis:',sum(-30,40))Output: TheSumis:70 TheSumis:10Theabovelambdafunctionthataddsargumentarg1withargumentarg2andstorestheresultinthevariablesum.Theresultisdisplayedusingtheprint().(iii) Functions using librariesBuilt-in and Mathematical functions

Function Description Syntax Exampleabs() Returnsanabsolutevalueof

anumber.The argument may be aninteger or a floating pointnumber.

abs(x)

x=20y=-23.2print('x=',abs(x))print('y=',abs(y))Output: x=20 y=23.2


ord() Returns theASCII value forthegivenUnicodecharacter.This function is inverse ofchr()function. ord(c)

c='a'd='A'print('c=',ord(c))print('A=',ord(d))Output: c = 97 A = 65

(iv) Recursive functionsWhenafunctioncallsitselfisknownasrecursion.Recursionworkslikeloopbutsometimesitmakesmoresensetouserecursionthanloop.Youcanconvertanylooptorecursion.Example: deffact(n): ifn==0: return1 else: returnn*fact(n-1) print(fact(0)) print(fact(5)) Output: 1 120

36(a) (i)Therange()isafunctionusedtogenerateaseriesofvaluesinPython.Usingrange()function,youcancreatelistwithseriesofvalues.Therange()functionhasthreearguments.

Syntax of range ( ) function: range (start value, end value, step value)where,•start value – beginningvalueofseries.Zeroisthedefaultbeginningvalue.•end value – upperlimitofseries.Pythontakestheendingvalueasupperlimit–1.•step value – Itisanoptionalargument,whichisusedtogeneratedifferentintervalofvalues.Example : Generating whole numbers upto 10forxinrange(1,11): print(x)Output 1 2 3 4 5 6 7

ANSWERS G-53

8 9 10

(ii) Creating a list with series of valuesUsingtherange()function,youcancreatealistwithseriesofvalues.Toconverttheresultofrange()functionintolist,weneedonemorefunctioncalledlist().Thelist()functionmakestheresultofrange()asalist.Syntax: List_Varibale = list ( range ( ) )NoteThelist()functionisallsousedtocreatelistinpython.Example>>>Even_List=list(range(2,11,2))>>>print(Even_List)[2,4,6,8,10]Intheabovecode,list()functiontakestheresultofrange()asEven_Listelements.Thus,Even_Listlisthastheelementsoffirstfiveevennumbers.

(iii)Wecancreateanyseriesofvaluesusingrange()function.Thefollowingexampleexplainshowtocreatealistwithsquaresoffirst10naturalnumbers.

Example : Generating squares of first 10 natural numberssquares=[]forxinrange(1,11): s=x**2 squares.append(s) print(squares)Output [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

[OR] (b) print("Enter'x'forexit.") string1=input("Enterfirststring:") ifstring1=='x': exit(); else: string2=input("Entersecondstring:") print("\nBothstringsbeforeswap:") print("Firststring=",string1) print("Secondstring=",string2) temp=string1 string1=string2 string2=temp print("\nBothstringsafterswap:") print("Firststring=",string1)


print("Secondstring=",string2) Output: Enter'x'forexit Enterfirststring:code Entersecondstring:python Bothstringsbeforeswap: Firststring=code Secondstring=python Bothstringsafterswap: Firststring=python Secondstring=code 37(a) num=[] forxinrange(1,21): num.append(x) print("Thelistofnumbersfrom1to20=",num) forindex,iinenumerate(num): if(i%3==0) delnum[index] print("Thelistafterdeletingnumbers",num) Output: Thelistofnumbersfrom1to20=[1,2,3,4...20] Thelistafterdeletingnumbers[1,2,4,5,7,8,10,11,13,14,16,17,19,20]

[OR] (b) classstud: def__init__(self): self.name="" self.m1=0 self.m2=0 self.tot=0 defgdata(self): self.name=input("Enteryourname") self.m1 =int(input("Entermarks1")) self.m2 =int(input("Entermarks2")) self.tot =self.m1+self.m2 defdisp(self): print(self.name) print(self.m1) print(self.m2) print(self.tot) mlist=[] st=stud() st.gdata()

ANSWERS G-55

mlist.append(st) forxinmlist: x.disp() Output: Enteryourname Ram Entermarks1 100 Entermarks2 100 Ram100100 200 38(a) Constraintsensuredatabaseintegrity,thereforeknownasdatabaseintegrityconstraints.

Constraint

Unique Constraint

Primary Key Constraint

Default Constraint

Check Constraint

(i) Unique Constraint Thisconstraintensuresthatnotworowshavethesamevalueinthespecifiedcolumns.For

exampleUNIQUEconstraintappliedonAdmnoofstudenttableensuresthatnotwostudentshavethesameadmissionnumberandtheconstraintcanbeusedas:

CREATETABLEStudent ( Admno integer NOT NULL UNIQUE, → Unique constraint Name char (20) NOT NULL, Gender char (1), Age integer, Place char (10), ); TheUNIQUEconstraintcanbeappliedonlytofieldsthathavealsobeendeclaredasNOT

NULL. Whentwoconstraintsareappliedonasinglefield,itisknownasmultipleconstraints.Inthe

aboveMultipleconstraintsNOTNULLandUNIQUEareappliedonasinglefieldAdmno,theconstraintsareseparatedbyaspaceandattheendofthefielddefinitionacomma(,)isadded.ByaddingthesetwoconstraintsthefieldAdmnomusttakesomevaluei.e.willnotbeNULLandshouldnotbeduplicated.

(ii) Primary Key Constraint ThisconstraintdeclaresafieldasaPrimarykeywhichhelpstouniquelyidentifyarecord.It

issimilartouniqueconstraintexceptthatonlyonefieldofatablecanbesetasprimarykey.TheprimarykeydoesnotallowNULLvaluesandthereforeafielddeclaredasprimarykeymusthavetheNOT NULLconstraint.

ExampleshowingPrimaryKeyConstraintinthestudenttable: CREATE TABLE Student (


Admno integer NOT NULL PRIMARY KEY, → Primary Key constraint Name char(20)NOT NULL, Gender char(1), Age integer, Place char(10), ); IntheaboveexampletheAdmnofieldhasbeensetasprimarykeyandthereforewillhelp

ustouniquelyidentifyarecord,itisalsosetNOT NULL,thereforethisfieldvaluecannotbeempty.

(iii) DEFAULT Constraint TheDEFAULTconstraintisusedtoassignadefaultvalueforthefield.Whennovalueis

givenforthespecifiedfieldhavingDEFAULTconstraint,automaticallythedefaultvaluewillbeassignedtothefield.

ExampleshowingDEFAULTConstraintinthestudenttable: CREATE TABLE Student ( Admno integer NOT NULL PRIMARY KEY, Name char(20) NOT NULL, Gender char(1), Age integer DEFAULT = "17", → Default Constraint Place char(10), ); Intheaboveexamplethe"Age"fieldisassignedadefaultvalueof17,thereforewhenno

valueisenteredinagebytheuser,itautomaticallyassigns17toAge. (iv) Check Constraint Thisconstrainthelpstosetalimitvalueplacedforafield.Whenwedefineacheckconstraint

onasinglecolumn,itallowsonlytherestrictedvaluesonthatfield. Exampleshowingcheckconstraintinthestudenttable: ( Admno integer NOT NULL PRIMARY KEY Name char(20)NOT NULL, Gender char(1), Age integer (CHECK<=19), → Check Constraint Place char(10), ); IntheaboveexamplethecheckconstraintissettoAgefieldwherethevalueofAgemustbe

lessthanorequalto19. Note: Thecheckconstraintmayuserelationalandlogicaloperatorsforcondition. (v) TABLE CONSTRAINT Whentheconstraintisappliedtoagroupoffieldsofthetable,itisknownasTableconstraint.

ANSWERS G-57

Thetableconstraintisnormallygivenattheendofthetabledefinition.LetustakeanewtablenamelyStudent1withthefollowingfieldsAdmno,Firstname,Lastname,Gender,Age,Place:

CREATE TABLE Student 1 ( Admno integer NOT NULL, Firstname char(20), Lastname char(20), Gender char(1), Age integer, Place char(10), PRIMARY KEY (Firstname, Lastname) → Table constraint ); Intheaboveexample,thetwofields,FirstnameandLastnamearedefinedasPrimarykey

whichisaTableconstraint.

[OR]

(b) importcsvrow=['3','Meena','Bangalore']withopen('student.csv','r')asreadFile:reader=csv.reader(readFile)lines=list(reader) # list()- to store each row of data as a listlines[3]=rowwithopen('student.csv','w')aswriteFile:# returns the writer object which converts the user data with delimiterwriter=csv.writer(writeFile)#writerows()method writes multiple rows to a csv filewriter.writerows(lines)readFile.close()writeFile.close()Whenweopenthestudent.csvfilewithtexteditor,thenitwillshow:

Roll No Name City1 Harshini, Chennai2 Adhith, Mumbai3 Meena, Bengaluru4 egiste, Tiruchy5 Venkat, Madurai



25. welcome–modulename.–dotoperator

display()–functionname 26. (i)ChooseRun→RunModuleorPressF5

(ii) Ifyourcodehasanyerror,itwillbeshowninredcolorintheIDLEwindow,andPythondescribesthetypeoferroroccurred.Tocorrecttheerrors,gobacktoScripteditor,makecorrections,savethefileusingCtrl+SorFile→Saveandexecuteitagain.

(iii)Forallerrorfreecode,theoutputwillappearintheIDLEwindowofPython. 27. •SQLiteisasimplerelationaldatabasesystem,whichsavesitsdatainregulardatafilesor

evenintheinternalmemoryofthecomputer.•Itisdesignedtobeembeddedinapplications,insteadofusingaseparatedatabaseserver programsuchasMySQLorOracle.•SQLiteisfast,rigorouslytested,andflexible,makingiteasiertowork.Pythonhasanative libraryforSQLite.

28. Displaying A record using fetchone()Thefetchone()methodreturnsthenextrowofaqueryresultsetorNoneincasethereisnorowleft.Exampleimportsqlite3connection=sqlite3.connect("Academy.db")cursor=connection.cursor()cursor.execute("SELECT*FROMstudent")print("\nfetchone:")res=cursor.fetchone()print(res)

ANSWERS G-59

OUTPUT fetchone: (1,'Akshay','B','M',87.8,'2001-12-12')Displayingusing fetchmany()Displayingspecifiednumberofrecordsisdonebyusingfetchmany().Thismethodreturnsthenextnumberofrows(n)oftheresultset.Example : Program to display the content of tuples using fetchmany()importsqlite3connection=sqlite3.connect("Academy.db")cursor=connection.cursor()cursor.execute("SELECT*FROMstudent")print("fetchingfirst3records:")result=cursor.fetchmany(3)print(result)OUTPUTfetchingfirst3records:[(1,'Akshay','B','M',87.8,'2001-12-12'),(2,'Aravind','A','M',92.5,'2000-08-17'),(3,'BASKAR','C','M',75.2,'1998-05-17')]

29. ClassesandObjectsarethekeyfeaturesofObjectOrientedProgramming.ClassisthemainbuildingblockinPython.Objectisacollectionofdataandfunctionthatactonthosedata.Classisatemplatefortheobject.AccordingtotheconceptofObjectOrientedProgramming,objectsarealsocalledasinstancesofaclassorclassvariable.

30. (i)Theelementsofalistarechangeable(mutable)whereastheelementsofatupleare unchangeable(immutable),thisisthekeydifferencebetweentuplesandlist. (ii)Theelementsofalistareenclosedwithinsquarebrackets.But,theelementsofatuple

areenclosedbyparanthesis. (iii)Iteratingtuplesisfasterthanlist. 31. A set is created by placing all the elements separated by commawithin a pair of curly

brackets. Theset()functioncanalsousedtocreatesetsinPython. Syntax: Set_Variable={E1,E2,E3……..En} Example >>>S1={1,2,3,'A',3.14} >>>print(S1) {1,2,3,3.14,'A'} >>>S2={1,2,2,'A',3.14} >>>print(S2) {1,2,'A',3.14}


32. Program to create a list of numbers from 1 to 20 that are divisible by 4 divBy4=[] foriinrange(21): if(i%4==0): divBy4.append(i) print(divBy4) Output: [0,4,8,12,16,20] 33. Constructorofclasssample... Thevalueis:10

PART - IV 34(a) InPython,aclass isdefinedbyusing thekeywordclass.Everyclasshasauniquename

followedbyacolon(:).Syntax: class class_name: statement_1 statement_2 ………….. ………….. statement_nWhere,statementinaclassdefinitionmaybeavariabledeclaration,decisioncontrol,looporevenafunctiondefinition.Variablesdefinedinsideaclassarecalledas"ClassVariable"andfunctionsarecalledas"Methods".Classvariableandmethodsaretogetherknownasmembersoftheclass.Theclassmembersshouldbeaccessedthroughobjectsorinstanceofclass.AclasscanbedefinedanywhereinaPythonprogram.Example:Programtodefineaclass classSample: x,y=10,20 # class variablesIntheabovecode,nameoftheclassisSampleandithastwovariablesxandyhavingtheinitialvalue10and20respectively.Toaccessthevaluesdefinedinsidetheclass,youneedanobjectorinstanceoftheclass.

[OR] (b) (i) Union: Itincludesallelementsfromtwoormoresets. Inpython,theoperator|isusedtounionoftwosets.Thefunctionunion()isalsousedtojoin

twosetsinpython. Example:ProgramtoJoin(Union)twosetsusingunionoperator set_A={2,4,6,8} set_B={'A','B','C','D'} U_set=set_A|set_B print(U_set)

Set A Set B

ANSWERS G-61

Output: {2,4,6,8,'A','D','C','B'} (ii) Intersection:Itincludesthecommonelementsintwosets Theoperator&isusedtointersecttwosetsinpython.Thefunctionintersection()isalso

usedtointersecttwosetsinpython. Example:Programtoinsecttwosetsusingintersectionoperator set_A={'A',2,4,'D'} set_B={'A','B','C','D'} print(set_A & set_B) Output: {'A','D'}

(iii) Difference:Itincludesallelementsthatareinfirstset(saysetA)butnotinthesecondset(saysetB)

Theminus(-)operatorisusedtodifferencesetoperationinpython. Thefunctiondifference()isalsousedtodifferenceoperation. Example:Programtodifferenceoftwosetsusingminusoperator set_A={'A',2,4,'D'} set_B={'A','B','C','D'} print(set_A - set_B) Output: {2,4}

(iv) Symmetric difference:Itincludesalltheelementsthatareintwosets(saysetsAandB)butnottheonethatarecommontotwosets.


Example:Programtosymmetricdifferenceoftwosetsusingcaretoperator set_A={'A',2,4,'D'} set_B={'A','B','C','D'} print(set_A ^ set_B) Output: {2,4,'B','C'}

35(a) marks=[] subjects=['Tamil','English','Physics','Chemistry','Comp.Science','Maths'] foriinrange(6): m=int(input("EnterMark=")) marks.append(m) forjinrange(len(marks)): print("{}.{}Mark={}".format(j1+,subjects[j],marks[j])) print("TotalMarks=",sum(marks)) Output EnterMark=45

Set A Set B

Set A Set B

Set A Set B


EnterMark=98 EnterMark=76 EnterMark=28 EnterMark=46 EnterMark=15 1.TamilMark=45 2.EnglishMark=98 3.PhysicsMark=76 4.ChemistryMark=28 5.Comp.ScienceMark=46 6.MathsMark=15 TotalMarks=308

[OR]

(b) classSample: def__init__(self,n1,n2): self.__n1=n1 self.__n2=n2 defdisplay(self): print("classvariable1:",self.__n1) print("classvariable2:",self.__n2) print("sum:",self.__n1+self.__n2) s=sample(10,20) s.display() Output: classvariable1:10 classvariable2:20 sum:30

36(a) CharacteristicsofDatabaseManagementSystem.

1. DatastoredintoTables

Dataisneverdirectlystoredintothedatabase.Dataisstoredintotables,createdinsidethedatabase.DBMSalsoallowstohave relationshipbetween tableswhichmakes thedatamoremeaningfulandconnected.

2. ReducedRedundancy

Inthemodernworldharddrivesareverycheap,butearlierwhenharddrivesweretooexpensive,unnecessaryrepetitionofdataindatabasewasabigproblemButDBMSfollowsNormalisation which divides the data in such a way thatrepetitionisminimum.

ANSWERS G-63

3. DataConsistencyOnlivedata,itisbeingcontinuouslyupdatedandadded,maintainingtheconsistencyofdatacanbecomeachallenge.ButDBMShandlesitbyitself.

4.SupportMultipleuserandConcurrentAccess

DBMSallowsmultipleuserstoworkonit(update,insert,deletedata)atthesametimeandstillmanagestomaintainthedataconsistency.

5. QueryLanguageDBMSprovidesuserswithasimplequerylanguage,usingwhichdatacanbeeasilyfetched,inserted,deletedandupdatedinadatabase.

6. Security

TheDBMSalsotakescareofthesecurityofdata,protectingthedatafromunauthorizedaccess.InatypicalDBMS,wecancreateuseraccountswithdifferentaccesspermissions,usingwhichwecaneasilysecureourdatabyrestrictinguseraccess.

7. DBMSSupportsTransactions

It allowsus tobetterhandleandmanagedata integrity inrealworldapplicationswheremulti-threadingisextensivelyused.

[OR]

(b) (a) CREATE TABLE Command YoucancreateatablebyusingtheCREATETABLEcommand. CREATETABLEStudent (Admnointeger, Namechar(20),\ Genderchar(1), Ageinteger, Placechar(10), ); (b) ALTER COMMAND TheALTERcommandisusedtoalterthetablestructurelikeaddingacolumn,renaming

theexistingcolumn,changethedatatypeofanycolumnorsizeofthecolumnordeletethecolumnfromthetable.

AltertableStudentaddaddresschar; (c) DROP TABLE: Droptablecommandisusedtoremoveatablefromthedatabase. DROPTABLEStudent; 37(a) (i)Itshouldidentifythetypeofdatadivisionsuchasdataitem,segment,recordanddatabasefile. (ii) Itgivesauniquenametoeachdataitemtype,recordtype,filetypeanddatabase. (iii)Itshouldspecifytheproperdatatype. (iv) Itshoulddefinethesizeofthedataitem.


(v) Itmaydefinetherangeofvaluesthatadataitemmayuse. (vi) Itmayspecifyprivacylocksforpreventingunauthorizeddataentry.

[OR]

(b) Read a CSV File Using Python TherearetwowaystoreadaCSVfile. (i) Usethecsvmodule’sreaderfunction (ii) UsetheDictReaderclass.

TwowaysofReadingCSVFile

reader()function DictReaderclassWays to read CSV file

(i) CSV Module’s Reader Function You can read the contents ofCSVfilewith the help of csv.reader()method.The reader

functionisdesignedtotakeeachlineofthefileandmakealistofallcolumns.Then,youjustchoosethecolumnyouwantthevariabledatafor.Usingthismethodonecanreaddatafromcsvfilesofdifferentformatslikequotes(""),pipe(|)andcomma(,).

The syntax for csv.reader() is csv.reader(fileobject,delimiter,fmtparams) where fileobject:- passesthepathandthemodeofthefile delimiter:- anoptionalparametercontainingthestandarddilectslike,Ietccanbeomitted fmtparams:- optionalparameterwhichhelptooverridethedefaultvaluesofthedialects

likeskipinitialspace,quotingetc.Canbeomitted

CSV file - data with default delimiter comma (,)

CSV file - data with Space at the beginning

CSV file - data with quotes

CSV file - data with customer Delimiters

(ii) Reading CSV File Into A Dictionary ToreadaCSVfileintoadictionarycanbedonebyusingDictReaderclassofcsvmodule

whichworkssimilartothereader()classbutcreatesanobjectwhichmapsdatatoadictionary.Thekeysaregivenbythefieldnamesasparameter.DictReaderworksbyreadingthefirstlineoftheCSVandusingeachcommaseparatedvalueinthislineasadictionarykey.Thecolumnsineachsubsequentrowthenbehavelikedictionaryvaluesandcanbeaccessedwiththeappropriatekey(i.e.fieldname).

ANSWERS G-65

IfthefirstrowofyourCSVdoesnotcontainyourcolumnnames,youcanpassafieldnamesparameter into theDictReader’s constructor to assign the dictionary keysmanually.Themaindifferencebetween the csv.reader() andDictReader() is in simple termscsv. readerand csv.writer work with list/tuple, while csv.DictReader and csv.DictWriter work withdictionary.csv.DictReaderandcsv.DictWritertakeadditionalargumentfieldnamesthatareusedasdictionarykeys.

38(a) Read A CSV File And Store It In A List InthistopicyouaregoingtoreadaCSVfileandthecontentsofthefilewillbestoredasa

list.ThesyntaxforstoringintheListis list=[] #Startastheemptylist list.append(element) #Useappend()toaddelements Forexampleall therowvaluesof"sample.csv"fileisstoredina listusingthefollowing

program importcsv #otherwayofdeclaringthefilename inFile='c:\\pyprg\\sample.csv' F=open(inFile,'r') reader=csv.reader(F) #declaringarray arrayValue=[] #displayingthecontentofthelist forrowinreader: arrayValue.append(row) print(row) F.close()

A1 V

1 Topic 3Topic 2Topic 1A B C

2 threetwoOne3 Example 3Example 2Example 14

fx

Sample5.cv File with selected col

OUTPT[`Topic1`, `Topic2`, `Topic3`][òne`, `two`, `three`][Èxample1`, Èxample2`, Èxample3`]

Topic 1

[OR]


(b) Multiplication table num=int(input("Enterthenumber:")) print("multiplicationTableof",num) foriinrange(1,11): print(num,"x",i,"=",num*i)Output:Enterthenumber:6MultiplicationTableof6 6x1=6 6x2=12 6x3=18 6x4=24 6x5=30 6x6=36 6x7=42 6x8=48 6x9=54 6x10=60

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