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 your answer to question N may be correct.
Comment out any code that causes errors and re-run Cell ► Run All
before submitting your notebook.
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 growing that takes an argument named x that is a list of floats. Your function should return a list containing the value 1 for each element that is smaller than the next one and 0 for each value that is not. For example, if x=[1, -1, 3, 0, 1] growing(x) should return a list containing [0, 1, 0, 1]. Note that the returned list will be one element shorter than the argument.
def growing(x):
return [1 if x[i]>x[i-1] else 0 for i in range(1,len(x))]
x=[1, -1, 3, 0, 1]
growing(x)
Write a function named sel2 that takes one dictionary argument named d. The keys of the dictionary d are strings and the values are lists of integers. Your function should create a new dictionary that has the same keys but each list replaced by the second integer in the corresponding list. For example if d = { 'a': [1, 3, 2], 'bb':[8, -1], 'f': [3, 11, 8, 8]} then sel2(d) should return the dictionary {'a': 3, 'bb': -1, 'f': 11}.
def sel2(d):
return {k:d[k][1] for k in d}
d = { 'a': [1, 3, 2], 'bb':[8, -1], 'f': [3, 11, 8, 8]}
sel2(d)
Write a recursive function named rint2str that takes an argument named l which is a list of integers and returns a list of strings. For example if l=[0, 1, -3] then rint2str(l) would return ['0', '1', '-3'].
def rint2str(l):
if not l:
return l
else:
return [str(l[0])]+rint2str(l[1:])
l=[0, 1, -3]
rint2str(l)
Set the variable pat to a regular expression that matches a part number string created according to the following sequence:
For example, re.search(pat,'MGA1234YKSZ-REEL7') would return a match object but re.search(pat,'MGB1234YKSZ-REEL7') would not.
pat=r'^(MGA|ADA)\d{3,4}(YK|BRU|CRU)[ST]Z?(-REEL7)?$'
import re
print(re.search(pat,'MGA1234YKSZ-REEL7'))
print(re.search(pat,'MGB1234YKSZ-REEL7'))
# exam validation code; do not modify
def examcheck():
import copy, hashlib, re
from random import randint, choices, shuffle, sample
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 checksorted(l):
assert all((l[i] <= l[i+1] for i in range(len(l)-1))), \
"result is not sorted: {}".format(l)
def checkfunctions(f,l):
u=[s for s in f.__code__.co_names if s not in l]
assert not u, "You used the function(s): {}".format(u)
def checkrecursive(f):
s=f.__name__
assert s in f.__code__.co_names, "{} is not recursive".format(s)
def checkhash(l,n):
# print(hashlib.md5(''.join(l).encode('utf8')).hexdigest())
assert hashlib.md5(''.join(l).encode('utf8')).hexdigest() == n, \
'wrong values in list: {} ... {}'.format(l[0],l[-1])
def checkre(pat,ok,nok):
for s in ok:
assert re.search(pat,s), \
"pattern '{}' didn't match string '{}'".format(pat,s)
for s in nok:
assert not re.search(pat,s), \
"pattern '{}' matched string '{}'".format(pat,s)
def q1():
import random
n=randint(5,9)
x=[random.random()*100 for _ in range(n)]
x0=copy.copy(x)
y=growing(x)
assert len(y) == n-1 and all([a<b for a,b,t in zip(x0,x0[1:],y) if t]), \
"growing({}) returns: {}".format(x0,y)
def q2():
n=randint(3,5)
wl=randwords(n)
nl=[sample(range(10,100),k=randint(3,5)) for i in range(n)]
d={k:v for k,v in zip(wl,nl)}
d0=copy.deepcopy(d)
y=sel2(d)
assert len(y) == n and set(d0.keys()) == set(y.keys()) and \
all([y[k] == d0[k][1] for k in d0]), "sel2({}) returns {}".format(d0,y)
def q3():
n=randint(3,5)
l=sample(range(-9,9),k=n)
l0=copy.copy(l)
y=rint2str(l)
checkrecursive(rint2str)
assert len(y) == n and all((type(i) == str for i in y)) and \
all((int(s) == i for i,s in zip(l0,y))), \
"rint2str({}) returns {}".format(l0,y)
def q4():
ok=['MGA1234YKSZ-REEL7', 'ADA1234YKSZ-REEL7', 'MGA999YKSZ-REEL7',
'MGA1234BRUSZ-REEL7', 'MGA1234CRUSZ-REEL7', 'MGA1234YKTZ-REEL7',
'MGA1234YKT-REEL7', 'MGA1234YKT']
nok=[' MGA1234YKSZ-REEL7', 'MGB1234YKSZ-REEL7', 'MGA12YKSZ-REEL7',
'MGA1234YSZ-REEL7', 'MGA1234YKA-REEL7', 'MGA1234YKSZ-REEL' ]
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("Solution to question {} may be correct.".format(i))
except Exception as e:
print("Failed check for question {}: {}".format(i,e))
examcheck()