CompSci 101 Sec 02, Fall 2014, Exam 2 Solutions

Problem 1

['fa', 'me', 're', 'so']

['la', 'me', 're', 'do']

set([8, 6])
set([2, 4, 6, 8, 10, 13])
set([2, 4, 10, 13])

Y
['Duke', 'ECU', 'UNC', 'WFU']
set(['Y', 'P', 'B'])

['B', 'G', 'Y']
WFU     OR    UNC


Problem 2

A.
[15, 9, 3]
[5, 8]
5

B. 
containsA = [x for x in words if 'a' in x or 'A' in x]
 
OR

containsA = [x for x in words if 'a' in x.lower()]
 
OR

containsA = [x for x in words if x.count('a')>0 or x.count('A')>0]


C. 
firstThree = [item[0:3] for item in words if len(item) > 5]

OR

firstThree = [item[:3] for item in words if len(item) > 5]

Problem 3 
A. 
def fileToList(fileMeals):
    answer = []
    for line in fileMeals:
        line = line.strip()
        answer.append(line.split(":"))
    return answer

OR

return [line.strip().split(":")  for line in fileMeals]

B. 
def foodEaten(data, name):  
    food = []
    for item in data:
        fullname = item[2].split(" ")
        if fullname[-1] == name:
            food.append(item[0])
    return food

OR

def foodEaten(data, name):  
    return [item[0] for item in data if item[2].split()[-1] == name]



Problem 4

A. 
def listOfSchools(data):
    setSchools = set([])
    for item in data:
        setSchools.add(item[0])
    alist = list(setSchools)
    alist.sort()
    return alist    

OR

def listOfSchools(data):
    listSchools = []
    for item in data:
        listSchools.append(item[0])
    alist = list(set(listSchools))
    alist.sort()
    return alist

OR
 
def listOfSchools(data):
    listSchools = []
    for item in data: 
        if item[0] not in listSchools:
            listSchools.append(item[0])
    return sorted(listSchools)
OR

def listOfSchools(data):
    return sorted(list(set([item[0] for item in data])))

B. 
def problemsSolved(data):
    problems = set([])
    for item in data:
        if item[3] == "correct":
            problems.add(item[1])
    return list(problems)

OR

def problemsSolved(data):
    solved = []
    for item in data:
        if item[3] == "correct" and item[1] not in solved:
            solved.append(item[1])
    return solved

C. 
def problemsNotSolved(problems, data):
    solved = problemsSolved(data)
    setProbs = set(problems)
    setSolved = set(solved)
    setNotSolved = setProbs.difference(setSolved)
    return list(setNotSolved)

OR

def problemsNotSolved(problems, data):
    notSolved = []
    solved = problemsSolved(data)
    for pr in problems:
        if pr not in solved:
            notSolved.append(pr)
    return notSolved

D. 
def dictSchoolToSolvedProblems(data):
    d = {}
    for item in data:
        if item[3] == 'correct':
            if item[0] in d:
                d[item[0]].append(item[1]) 
            else:
                d[item[0]] = [item[1]]
    return d
        
E. 
def dictSchoolToScore(data):        
    schools = listOfSchools(data)
    d = {}
    for school in schools:
        d[school] = totalScoreSchool(data, school)
    return d

F. 
def winner(data):
    d = dictSchoolToScore(data)
    win = ("", 0)
    for (key,value) in d.items():
        if value > win[1]:
            win = (key,value)
    return win      

OR

def winner(data):
    d = dictSchoolToScore(data)
    maxScore = max([d[key] for key in d])
    for (key,value) in d.items():
        if value == maxScore    # found it
            return (key,value)
    return ("",0)               # It should match something, but just in case