Tome Rater Instructions

User Manual:

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Introduction

Inthiscapstone,youwillcreateanapplicationcalledTomeRaterthat

allowsuserstoreadandratebooks.

Thepurposeofthiscapstoneistopracticeimplementingandtesting

classesinPython.Youwillbegivenspecificationsformethodsfor5

differentclassesthatinteractwitheachother.Tocreatethesemethodsyou

willuseyourknowledgeoflists,loops,dictionaries,strings,controlflow,

andofcourse,basicPythonsyntax!Ifyouneedtorefreshyourmemoryof

theseconcepts,gobacktotheselessonsinthesyllabus.

Comparedtotheotherprojectsyouhavecompletedthisfar,weare

requiringfewrestrictionsonhowyoustructureyourcode.Inaddition,

muchofthecodeyouwriteforlaterpartsofthisprojectwilldependon

howyoudecidedtoimplementearlierparts.Therefore,westrongly

encourageyoutoreadthroughtheentireassignmentbeforewriting

anycode.

CreateaUser

Wewillneedtokeeptrackofourusers.Wehaveprovidedaskeletonfora

UserobjectinTomeRater.py.Openthisfileinyourtexteditor.Weare

goingtoreplacethe pass keywordsyousee,sothatthesemethodswork.

TheUserclassshouldhave:

Aconstructormethod,whichtakesin self , name ,and email .It

shouldsetinstancevariables self.name , self.email ,and

self.books .

name willbeastring

email willbeastring

self.books isanemptydictionarythatwillmapaBook

object(whichwewillcreate!)tothisuser’sratingofthe

book

Amethod get_email thatreturnstheemailassociatedwiththis

user

Amethod change_email thattakesinanewemailandchanges

theemailassociatedwiththisuser.Itshouldalsoprintamessage

sayingthatthisuser’semailhasbeenupdated.

A __repr__ methodthatreturnsastringtoprintoutthisuser

objectinameaningfulway.PrintingausernamedStephen

Hawking,withanemailhawking@universe.edu,with7booksread,

mightproduceastringlike:

UserStephenHawking,email:hawking@universe.edu,booksread

:7

butyoucancreateyourownformatforastringthatismosthelpfulforyou

tounderstandtheuserobjectbeingprinted.

An __eq__ methodtodefinecomparisonbetweenusers.AUser

objectshouldbeequaltoanotherUserobjectiftheybothhavethe

samenameandemail.

CreateaBook

OurUserobjectswillbereadingbooks.Butwhatisabook?DefineaBook

objectthathas:

Aconstructormethod,whichtakesin self , title ,and isbn .It

shouldsetinstancevariables self.title and self.isbn .It

shouldalsosetaninstancevariable self.ratings ,whichwill

startasanemptylist.

title willbeastring

isbn willbeanumber

Amethod get_title thatreturnsthetitleofthebook.

Amethod get_isbn thatreturnstheISBNofthebook

Amethod set_isbn thattakesinanewISBNandsetsthebook’s

isbn tobethisnewnumber.Itshouldalsoprintamessagesaying

thatthisbook’sISBNhasbeenupdated.

Amethodcalled add_rating thattakesina rating andaddsitto

thelist self.ratings .Itshouldonlydothisif rating isavalid

rating(atleast 0andatmost 4).Otherwise,itshouldprint

"InvalidRating" .

An __eq__ methodtodefinecomparisonbetweenbooks.ABook

objectshouldbeequaltoanotherBookobjectiftheybothhavethe

sametitleandisbn.

MakeaFictionSubclassofBook

Booksarenotallcreatedequal.Let’sassumewehavetwokindsofbooks,

fictionandnon-fiction.

The Fiction classshouldinheritfromBookandhavethefollowing

methods:

Aconstructor,whichtakesin self , title , author ,and isbn .It

shouldfirstcallthe __init__ ofitsparentclass,with title and

isbn .Then,itshouldsettheinstancevariable self.author .

get_author ,whichreturnstheauthor

__repr__ ,whichwillreturnthestring:

{title}by{author}

Forexample,thebookwithtitle“AliceInWonderland”andauthor“Lewis

Carroll”wouldprint:

AliceInWonderlandbyLewisCarroll

MakeaNon-FictionSubclassof

Book

The Non_Fiction classshouldinheritfromBookandhavethefollowing

methods:

Aconstructor,whichtakesin self , title , subject , level and

isbn .Itshouldfirstcallthe __init__ ofitsparentclass,with

title and isbn .Then,itshouldsettheinstancevariables

self.subject and self.level .

subject willbeastring,like "Geology"

level willbeastring,like "advanced"

get_subject ,whichreturnsthesubject

get_level ,whichreturnsthelevel

__repr__ ,whichwillreturnthestring:

{title},a{level}manualon{subject}

Forexample,thebookwithtitle“SocietyofMind”aboutbeginnerArtificial

Intelligencewouldprintout:

SocietyofMind,abeginnermanualonArtificialIntelligence

GiveBooksandUsersMethods

NowthatwehavebothBookclassesandUserclasses,wecancreatemore

methodsthanjustonesthatgetandsetinstancevariables.

ForyourUserclass,addtwomethods:

read_book ,whichtakesin book andanoptionalparameter

rating ,whichdefaultsto None .Itshouldaddakey:valuepairto

self.books wherethekeyis book andthevalueis rating .

get_average_rating ,whichiteratesthroughallofthevaluesin

self.books ,whicharetheratings,andcalculatestheaverage

rating.Itshouldreturnthisaverage.

ForyourBookclass,addthemethod:

get_average_rating ,whichiteratesthroughallofthevaluesin

self.ratings andcalculatestheaveragerating.Itshouldreturn

thisaverage.

ThereisonemoremethodwehavetoaddtoBooktomakethiswork!Do

yourememberhowwegettheerror TypeError:unhashabletype:

'list' ,whenwetrytocreateadictionarywithlistsaskeys?Thisis

becauselistsaremutable,andthusdonothaveaconsistent

hash

thata

dictionarycanusetolookuptheassociatedvalue.Wearetryingtomakea

dictionaryintheUserclasscalled self.books thathasBookobjectsas

keys.Inordertouseaclassthatweconstructourselves,wemustmake

surethatourobjectis hashable ,andnot unhashable ,likealist!

TomakeourBookhashable,wewilladdamethod __hash__ whichwill

returnaconsistenthashforaninstanceofabookobject:

def__hash__(self):

returnhash((self.title,self.isbn))

CopythismethodintoyourBookclasssothatBookbecomeshashable!If

you’recurious,lookatthedocumentationtoseewhatthebuilt-inmethod

hash() isdoing:https://docs.python.org/3/library/functions.html#hash

CreateTomeRater

WehaveUsersandBooks,buthowdotheyinteract?Nowit’stimeto

createtheapplicationtostorethoseusers.ItistimetocreateTomeRater!

Createaclass TomeRater thathasthefollowingmethods:

Aconstructorthatonlytakesin self .Itshouldcreate:

self.users ,anemptydictionarythatwillmapauser’semailto

thecorrespondingUserobject

self.books ,anemptydictionarythatwillmapaBookobjectto

thenumberofUsersthathavereadit

create_book ,whichtakesin title and isbn andcreatesanew

bookwiththattitleandISBN.ReturnsthisBookobject.

create_novel ,whichtakesin title , author ,and isbn ,and

createsanewFictionwiththattitle,authorandISBN.Returnsthis

Fictionobject.

create_non_fiction ,whichtakesin title , subject , level ,

and isbn ,andcreatesanewNon_Fictionwiththattitle,author

andISBN.ReturnsthisNon_Fictionobject.

add_book_to_user ,whichtakesin book , email ,andanoptional

parameter rating ,whichdefaultsto None .Itshouldgettheuser

in self.users withthekey email .Ifthisuserdoesn’texist,it

shouldprintout`“Nouserwithemail{email}!”.Iftheuserexists,

itshould:

Call read_book onthisuser,with book and rating

Call add_rating on book ,with rating

CheckifthebookisinTomeRater’s self.books already.If

itisnot,addthekey book to self.books withavalueof1

(becauseoneuserhasreadit)

If book wasalreadyinthecatalog,increasethevalueofit

in self.books by1,becauseonemoreuserhasreadit.

add_user ,whichtakesin name , email ,andanoptionallistof

Books books thatdefaultsto None .ItshouldcreateanewUser

objectfrom name and email .Then,if books isprovided,itshould

loopthroughthelist,andaddeachBooktotheuser(usingthe

TomeRatermethod add_book_to_user )

CreateSomeAnalysisMethods

forTomeRater

Now,wehaveanapplicationthatkeepstrackofUsersandtheBooksthey

haveread.Weshouldaddsomemethodstobeabletoanalyzeour

collection.

Addthesemethodstothe TomeRater class:

print_catalog ,whichiteratesthroughallofthekeysin

self.books (whichareBookobjects),andprintsthem

print_users ,whichiteratesthroughallofthevaluesof

self.users (whicharetheUserobjects),andprintsthem

most_read_book ,whichshoulditeratethroughallofthebooksin

self.books andreturnthebookthathasbeenreadthemost.

Rememberthatthekeysof self.books areBooks,andthevalues

arehowmanytimesthey’vebeenread.

highest_rated_book ,whichshoulditeratethroughallofthe

booksin self.books andreturnthebookthathasthehighest

averagerating.Rememberthatthekeysof self.books areBooks,

andyoucancall book.get_average_rating() onaBookobject

book .

most_positive_user ,whichshoulditeratethroughallofthe

usersin self.users andreturntheuserthathasthehighest

averagerating.Rememberthatthevaluesof self.users are

Users,andyoucancall user.get_average_rating() onaUser

object user .

DoSomeAnalysis

Openyourcommandlineandnavigatetothe

TomeRater

directory:

cdTomeRater

Runthefile

populate.py

,usingthecommand:

python3-ipopulate.py

Thisfile,populate.py,willcreateaTomeRaterobjectcalled Tome_Rater

andfillitwithsomeusersandbooks.The -i flagwillleavetheterminal

openforyoutoplaywith.Youcanthenrunsomeofyourmethodsyou

createdinthelastsectionbyusingsyntaxlike:

Tome_Rater.most_positive_user()

Goaheadandopenpopulate.pyinyourtexteditoraswellandlookatthe

objectsthatarebeingcreatedandused.Addyourowntests,toseeifyour

applicationworksthewayyouexpectitto!

GetCreative!

Incredible!Youhaveanapplicationthatstoresusersandbooks!You

basicallyownastartupnow.Totakeyourprojecttothenextlevel,choose

oneofthefollowingextensionideastoimplement:

Addmoresophisticatederrortesting!Thiscouldinclude:

Ifsomeonetriestoaddauserwithanemailthatalready

existsinTomeRater,printoutamessagetellingthemthat

thisuseralreadyexists

MakesurethatbooksallhaveuniqueISBNs

Makesurethatanemailaddressisvalidbycheckingifit

hasan @characterandeither .com , .edu , .org

Addsome

dundermethods

tothe TomeRater classaswell:

Whatshoulditlooklikeifa TomeRater objectisprinted?

Whatwoulditmeanfortwo TomeRater objectstobe

equal?

Addmoresophisticatedanalysismethodslike:

get_n_most_read_books ,whichwouldtakeinanumber n

andreturnthe nbooksthathavebeenreadmost,in

descendingorder

get_n_most_prolific_readers ,whichwouldtakeina

number nandreturnthe nusersthathavereadthemost

books,indescendingorder

AddapricevariableforeachBooksothatyoucouldaddmethods

toTomeRaterlike:

get_n_most_expensive_books(self,n) ,whichwould

returnthe nbookswithhighestprice

get_worth_of_user(self,user_email) ,whichwould

returnthesumofthecostsofallthebooksreadbythisuser

YourownideaforhowtomakeTomeRaterbetter