CompSci Test 2 Section 02 Spring 2017
Problem 1

Part A is 13 points

['S', 'Y', 'C', 'B', 'U', 'E']
['S', 'J', 'Y', 'C']
['S', 'J', 'C']
['S', 'J']
[1, 3, 4, 5, 7]
[1, 3, 7]
set([2])                # elements in any order
set([2, 3, 4, 7, 8])    # elements in any order
set([8, 4])             # elements in any order
['D', 'F', 'J', 'M']
['D', 'F', 'H', 'J', 'M']
[2, 6, 6, 7, 8]
[('D', 6), ('F', 8), ('H', 6), ('J', 7), ('M', 2)]


Part B is 3 points

[50, 60, 70, 30]     # elements in any order
[4, 1, 1, 2]         # elements in any order
4


Problem 2

2A)
result is [6, 6, 3, 6]

2B)
result is ['aeekmrt', 'aeffgir', 'abbirt', 'act']

2C)
result =  "".join([word[i] for i in range(len(word)) if i%2 == 0 ])

2D)
def lastNames(namelist):
    d = {}
    for name in namelist:
        last = name.split()[-1]
        if last not in d:
            d[last] = 0
        d[last] += 1
    return sorted(d.items())


Problem 3

Part A

def setupList(filename):
    f = open(filename)
    answer = []
    for line in f:
        line = line.strip()
        line = line.split(":")
        price = float(line[3])
        if line[2] == 'W':
            price = price*float(line[4])
        answer.append([line[0], line[1], price])
    return answer

Part B

def groceryPurchases(data, custid, amount):
    answer = []
    for item in data:
        if item[0] == custid:
            if item[2] <= amount:
                answer.append((item[1], item[2]))
                amount -= item[2]
    return answer
    


Problem 4

Part A

# given a departure city, give a unique sorted list of arrival cities
def arrivalCities(datalist, dcity):
    answer = []
    for item in datalist:
        if item[1] == dcity:
            answer.append(item[2])
    return sorted(list(set(answer)))

Part B

# Given an airline, return the sorted unique list of cities 
# with flights that are longer than time
def longFlights(datalist, airline, time):
    answer = []
    for item in datalist:
        if item[0].split()[0] == airline and int(item[4]) > time:
            answer.append(item[1])
    return sorted(set(answer))


Part C

# given list of popular cities, return a unique sorted
# list of popular cities our data doesn't fly to
def citiesNotFlownTo(datalist,cities):
    adata = set()
    bdata = set(cities)
    for item in datalist:
        adata.add(item[2])    
        adata.add(item[1])
    return sorted(bdata - adata)        

ALT SOLN no sets:

def citiesNotFlownTo(datalist,cities):
    adata = []                # note this could also be a set
    for item in datalist:
        acity = item[1] 
        rcity = item[2]
        if acity not in adata, 
             adata.append(acity)
        if rcity not in adata, 
             adata.append(rcity)
    answer = []               # note this could also be a set
    for item in cities:
        if item not in adata:
             answer.append(item)
    return sorted(answer)


Part D
 
def cityMostFlights(datalist):
    d = {}
    for item in datalist:
        if item[1] not in d:
            d[item[1]] = 0
        d[item[1]] += 1
        if item[2] not in d:
            d[item[2]] = 0
        d[item[2]] += 1
    maxnum = max(d.values())
    for city in d:
        if d[city] == maxnum:
            return city

Part E

# return a dictionary of airlines to list of tuples:
# (flightname/number and minutes)
def dictAirlines(datalist):
    d = {}
    for item in datalist:
        airline = item[0].split()[0]
        if airline not in d:
            d[airline] = []
        d[airline].append((item[0],int(item[4])))
    return d


Part F

# return a list of tuples. The first tuple is the airline with 
# the most time in the air, and that total time. 
# The rest of the tuples are the 
# flight names and minutes for each flight from this airline.
def airlineLargestMinutes(datalist):
    d = dictAirlines(datalist)
    maxmin = 0
    maxairline = ""
    for airline in d:
        tuplist = d[airline]
        sum = 0
        for (flight,minutes) in tuplist:
            sum+= minutes 
        if sum > maxmin: # found new max
            maxmin = sum
            maxairline = airline
    answer = (maxairline,maxmin, d[maxairline]) 
    return answer