Answer all four (4) questions.
You have 110 minutes to complete the exam.
This is an open-book exam. All written material is allowed.
No electronic devices other than a flash drive and the lab PC may be used during the exam.
No communication with others (electronic, verbal, written or otherwise) is allowed during the exam. Violations will result in a mark of zero and disciplinary action.
Add the Python code described below in the cells provided.
Test your code using the menu item Cell ► Run All
The message Question n OK. at the bottom of the notebook means that no errors were found in your answer to question n.
When the exam time is over, save the notebook (the .ipynb file) and upload it to the appropriate Assignment folder on the course web site.
Write a function stringrep(l1) that takes a list of strings and returns a list containing strings made up by repeating each element of the string a number of times equal to the index of the string in the list.For example, if l = [ 'AB', 'CDE', 'xyz', 'z'] then stringrep(l) would return ['', 'CDE', 'xyzxyz', 'zzz']. Hint: multiplication (*) can be used to repeat a string.
Write a function valfilter(l) that takes a list of two-element tuples and returns a list of those tuples where the first element of each tuple is less than the value of the second element. For example, if l = [(1,2), (4,3), (5,6)] then valfilter(l) would return [(1, 2), (5, 6)].
Write a function named shout(l) that takes a list of strings l and returns a list containing each string l converted to upper case. For example, if l = ['abc', 'def', "xyz"] then shout(l) would return ['ABC', 'DEF', "XTZ"].
Write a string named license that is a regular expression that matches strings that consist of:
This regular expression will match, for example any of: '1ABC123', 'XYZ789',
but not any of: '11ABC123', 'ABc123', 'ABC123', 'AB123', 'ABCD123', 'ABC12', 'ABC1234', 'ABC'.
# exam validation code; do not modify
def examcheck():
import copy, random, re, string, types
from random import randint
from random import randint, choices, shuffle, random
def checkre(pat,ok,nok):
for s in ok:
assert re.fullmatch(pat,s), \
f"pattern '{pat}'\n did not match string '{s}'"
for s in nok:
assert not re.fullmatch(pat,s), \
f"pattern '{pat}'\n matched string '{s}'"
def randwords(n,chars=string.ascii_letters,nl=(2,5)):
l = set()
while len(l)<n:
l |= set((''.join([chars[randint(0,len(chars)-1)] for i in range(randint(*nl))]),))
return list(l)
def q1(): # stringrep(l)
n=randint(3,5)
l = randwords(n,string.ascii_uppercase,(1,4))
ol = copy.deepcopy((l))
r = stringrep(l)
assert len(r) == len(ol) and \
all([len(s) == n*len(ol[n]) for n,s in enumerate(r)]) and \
all([all([n==0 or s[i] == s[i%len(ol[n])] for i,c in enumerate(s)]) for n,s in enumerate(r)]), \
f"stringrep({ol}) returns {r}"
def q2(): #valfilter
n = randint(4,5)
l = [(randint(0,10), randint(0,10)) for i in range(n)]
ol = copy.deepcopy(l)
r=valfilter(l)
notused = set(ol) - set(r)
assert notused.union(set(r)) == set(ol) and \
all([a<b for a,b in r]) and all([a>=b for a,b in notused]), \
f"valfilter({ol}) returns {r}"
def q3(): #shout
n=randint(4,6)
l = randwords(n,string.ascii_letters,(1,4))
ol=copy.deepcopy(l)
r = shout(l)
assert len(r) == len(ol) and all([s.lower() == ol[i].lower() for i,s in enumerate(r)]) and \
all([s.isupper() for s in r]), \
f"shout({ol}) returns {r}"
def q4(): #license
ok = [(randwords(1,string.digits,(1,1))[0] if randint(0,1) else '')+
randwords(1,string.ascii_uppercase,(3,3))[0]+
randwords(1,string.digits,(3,3))[0] for i in range(randint(5,7))]
nok = "11ABC123 ABc123 AB123 AX123 ABCD123 ABC12 ABC1234 ABC".split()
checkre(license,ok,nok)
for s,i in [(s,s[1:]) for s in locals().keys() if re.search(r'q\d+',s)]:
try:
locals()[s]()
print(f"Question {i} OK.")
except Exception as e:
print(f"Failed check for question {i}: {e}")
examcheck()
Failed check for question 1: name 'stringrep' is not defined Failed check for question 2: name 'valfilter' is not defined Failed check for question 3: name 'shout' is not defined Failed check for question 4: first argument must be string or compiled pattern