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 Solution to question N may be correct. 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 dropbox on the course web site.
Write a function named bigvals(d,n) that takes a dict argument d and an integer argument n. d has integer keys and string values. Your function should return a list of all the values in d whose key is equal to or larger than n (in any order). For example, if d={97: 'a', 67: 'b', 92: 'c', 68: 'd'} and n=70 then bigvals(d,n) should return ['a', 'c'] (or ['c', 'a']).
def bigvals(d,n):
return [v for k,v in d.items() if k >= n]
d={97: 'a', 67: 'b', 92: 'c', 68: 'd'}
n=70
bigvals(d,n)
Write a function named totalize(d) that takes one dict argument named d. Each element of d is a list of numbers. Your function should modify d by replacing each list with the sum of the values in that list. For example if d = {'a':[1], 'b':[1,2], 'c':[-1,0,1]} then after calling totalize(d) the value of d will be {'a': 1, 'b': 3, 'c': 0}.
def totalize(d):
for k,v in d.items():
d[k]=sum(v)
d = {'a':[1], 'b':[1,2], 'c':[-1,0,1]}
totalize(d)
d
Write a recursive function named listsquares(n,m) that takes two integer arguments , n and m and returns a list of the squares of the values between n and m inclusive. If n is greater than m an empty list should be returned. If n is equal to m a list containing only the single value n*n should be returned. For example listsquares(2,5) would return [4, 9, 16, 25].
def listsquares(n,m):
if n > m:
return []
if n == m:
return [n*n]
else:
return [n*n]+listsquares(n+1,m)
listsquares(1,0),listsquares(10,10),listsquares(2,5)
Set the variable pat to a regular expression that matches a part number string created according to the following sequence:
PN: or Part=For example, re.search(pat,'PN:0123456XX-ND') would return a match object but re.search(pat,'PN:12345XX-ND') would not.
pat=r'(PN:|Part=)[0-9]{6,7}[XYZ]X?-ND$'
import re
re.search(pat,'PN:0123456XX-ND'),re.search(pat,'PN:12345XX-ND')
# exam validation code; do not modify
def examcheck():
import copy, hashlib, re
from random import randint, choices, shuffle
def randwords(n):
l = set()
while len(l)<n:
l |= set((''.join([chr(randint(97,122)) for i in range(randint(2,5))]),))
return list(l)
def checkrecursive(f):
s=f.__name__
assert s in f.__code__.co_names, "{} is not recursive".format(s)
def checkre(pat,ok,nok):
for s in ok:
assert re.search(pat,s), \
f"pattern '{pat}'\n did not match string '{s}'"
for s in nok:
assert not re.search(pat,s), \
f"pattern '{pat}'\n matched string '{s}'"
def q1():
k=list(set(choices(range(100),k=4)))
v=randwords(len(k))
n=randint(30,70)
d=dict(zip(k,v))
d0=copy.deepcopy(d)
y=bigvals(d,n)
z=list(map(lambda x:d0.__getitem__(x),filter(lambda x:x>=n,d0)))
assert len(z) == len(y) and all([a==b for a,b in zip(y,z)]), \
f'bigvals{d0,n} returns {y}'
def q2():
n=randint(2,3)
d={k:choices(range(-1,9),k=randint(2,4)) for k in randwords(n)}
d0=copy.deepcopy(d)
totalize(d)
import functools, operator
assert not any(list({k:functools.reduce(operator.add,l)-d[k]
for k,l in d0.items()}.values())), \
f'totalize(d)\n for d={d0}\n results in d={d}'
def q3():
import math
checkrecursive(listsquares)
l=listsquares(1,0)
assert l == [], f'listsquares(1,0) returns {l}'
l=listsquares(2,2)
assert l == [4], f'listsquares(2,2) returns {l}'
n=randint(0,3)
m=n+randint(3,5)
l=listsquares(n,m)
assert [int(math.sqrt(i)) for i in l] == list(range(n,m+1)), \
f'listsquares{n,m} returns {l}'
def q4():
import re
ok = [ 'PN:0123456XX-ND','Part=0123456XX-ND', 'PN:012345XX-ND',
'PN:0123456YX-ND','PN:0123456ZX-ND','PN:0123456X-ND',
'aaaPN:0123456XX-ND' ]
nok = [ 'N:0123456XX-ND','Part:0123456XX-ND','PN:01234567XX-ND',
'PN:01234XX-ND','PN:0123456AX-ND','PN:0123456XY-ND',
'PN:0123456XX-N','PN:0123456XX-Naaa' ]
checkre(pat,ok,nok)
for i,s in ((i,'q%d'%i) for i in range(1,20)):
if s in locals():
try:
locals()[s]()
print(f"Solution to question {i} may be correct.")
except Exception as e:
print(f"Failed check for question {i}: {e}")
examcheck()