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 named denoise(l) that takes a list l of floats and returns a list containing only the values in l whose absolute value is larger than or equal to 1. For example, if l=[1, 0, -1.01, 0.1, 2, -1e-6, 100, -1e-6] then denoise(l) would return [1, -1.01, 2, 100].
Write a function swap(l) that takes a list of two-element tuples and returns a list with the elements of each tuple in reverse order. For example, if l = [(1,2), (4,3), (5,6)] then swap(l) would return [(2, 1), (3, 4), (6, 5)].
Write a function named mixed(s) that takes a string s and returns the string s with the odd-numbered characters converted to lower-case and the even-numbered characters converted to upper case. For example, if s = "Quick Brown Fox." then mixed(s) would return "QuIcK BrOwN FoX.. Hints: you can index the characters of a string. The enumerate iterator.
Write a string named tube that is a regular expression that matches strings that consist of:
This regular expression will match, for example any of: '12AV7', '6V6', '0A2'
but not any of: 'X7', '200V7', '127', '12AUG6', '12AV', '12AV30'.
# 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(): # denoise(l1)
import random
n=randint(5,7)
l=[random.gauss(0,2) for i in range(n)]
ol = copy.deepcopy(l)
r = denoise(l)
weak = set(ol) - set(r)
# print(l,r)
assert all([abs(x)<1 for x in weak]) and all([abs(x)>1 for x in r]) and set(weak).union(set(r)) == set(ol), \
f"dotproduct({ol1},{ol2}) returns {r}"
def q2(): #swap
n = randint(4,5)
l = [(randint(0,10), randint(0,10)) for i in range(n)]
ol = copy.deepcopy(l)
r=swap(l)
# print(len(r) == len(ol), all([a in ol[i] and b in ol[i] for i,(a,b) in enumerate(r)]) ,all([a<=b for a,b in r]))
assert len(r) == len(ol) and all([a == ol[i][1] and b == ol[i][0] for i,(a,b) in enumerate(r)]), \
f"swap({ol}) returns {r}"
def q3(): #mixed
s = randwords(1,"aeiouy bcrst .-",(15,25))[0]
os=copy.deepcopy(s)
r = mixed(s)
assert len(r) == len(os) and r.lower() == os.lower() and \
all([not c.isalpha() or c.isupper() for c in r[0::2]]+[not c.isalpha() or c.islower() for c in r[1::2]]), \
f"mixed({os}) returns {r}"
def q4(): #tube
ok = [randwords(1,string.digits,(1,2))[0]+
randwords(1,string.ascii_uppercase,(2,2))[0]+
randwords(1,string.digits,(1,1))[0] for i in range(randint(5,7))]
nok = "X7 200V7 127 12AUG6 12AV 12AV30".split()
checkre(tube,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 'denoise' is not defined Failed check for question 2: name 'swap' is not defined Failed check for question 3: name 'mixed' is not defined Failed check for question 4: name 'tube' is not defined