Difference between revisions of "CSC111 Lab 9 2018"
(→Part 1: Preparation) |
|||
(11 intermediate revisions by the same user not shown) | |||
Line 1: | Line 1: | ||
[[User:Thiebaut|D. Thiebaut]] ([[User talk:Thiebaut|talk]]) 09:54, 1 April 2018 (EDT) | [[User:Thiebaut|D. Thiebaut]] ([[User talk:Thiebaut|talk]]) 09:54, 1 April 2018 (EDT) | ||
---- | ---- | ||
− | + | <onlydft> | |
<bluebox> | <bluebox> | ||
This lab deals with exceptions and creating classes. | This lab deals with exceptions and creating classes. | ||
− | The deadline for this lab is Friday 04/6/18 at 11:55 p.m. | + | The deadline for this lab is <strike>Friday 04/6/18</strike> Sunday 4/8/18, at 11:55 p.m. |
</bluebox> | </bluebox> | ||
Line 79: | Line 79: | ||
==Review Class Example== | ==Review Class Example== | ||
<br /> | <br /> | ||
− | * Below is an example we saw in class, and that is taken from Zelle. It | + | * Below is an example we saw in class, and that is taken from Zelle. It prompts the user for 3 integers, separated by comas, and then it outputs the root of the equation <tt>a x^2 + b x + c = 0</tt>. |
<br /> | <br /> | ||
::<source lang="python"> | ::<source lang="python"> | ||
+ | from math import sqrt | ||
def ZelleExample(): | def ZelleExample(): | ||
− | import | + | print( "solution to quadratic equation" ) |
+ | a, b, c = eval( input( "enter 3 coefficients (a,b,c) " ) ) | ||
+ | disc = sqrt( b*b - 4*a*c ) | ||
+ | root1 = (-b + disc )/ (2*a) | ||
+ | root2 = (+b + disc )/ (2*a) | ||
+ | print( "solutions: ", root1, root2 ) | ||
+ | |||
+ | ZelleExample() | ||
+ | |||
+ | </source> | ||
+ | <br /> | ||
+ | * Run this program a few times and first give it numbers that will correspond to valid roots of the equation. For example 2, 3, -4. | ||
+ | * Now try making the program crash entering values that will make the part in the square root negative: 2, 1, 4. | ||
+ | * Notice the error you get: <tt><font color="red">ValueError: math domain error</font></tt>. | ||
+ | * Add a '''try/except''' statement to protect the whole block: | ||
+ | ::<source lang="python"> | ||
+ | def ZelleExample(): | ||
+ | from math import sqrt | ||
print( "solution to quadratic equation" ) | print( "solution to quadratic equation" ) | ||
try: | try: | ||
a, b, c = eval( input( "enter 3 coefficients (a,b,c) " ) ) | a, b, c = eval( input( "enter 3 coefficients (a,b,c) " ) ) | ||
− | disc = | + | disc = sqrt( b*b - 4*a*c ) |
root1 = (-b + disc )/ (2*a) | root1 = (-b + disc )/ (2*a) | ||
root2 = (+b + disc )/ (2*a) | root2 = (+b + disc )/ (2*a) | ||
print( "solutions: ", root1, root2 ) | print( "solutions: ", root1, root2 ) | ||
− | except | + | except ValueError: |
+ | print( "No real roots, negative discriminant" ) | ||
+ | |||
+ | |||
+ | ZelleExample() | ||
+ | </source> | ||
+ | <br /> | ||
+ | * Run your program again with 2, 1, 4 as input and verify that you now catch the ValueError exception. | ||
+ | * Continue testing your program with different inputs (try fewer than 3 number, forgetting a coma, inputing a string with the number, or providing 0 as the first number. | ||
+ | * Every time your program crashes, figure out the name of the exception and add it in a new '''except''' clause. | ||
+ | * Your code should looks something like this at some point... | ||
+ | <br /> | ||
+ | ::<source lang="python"> | ||
+ | def ZelleExample(): | ||
+ | from math import sqrt | ||
+ | print( "solution to quadratic equation" ) | ||
+ | try: | ||
+ | a, b, c = eval( input( "enter 3 coefficients (a,b,c) " ) ) | ||
+ | disc = sqrt( b*b - 4*a*c ) | ||
+ | root1 = (-b + disc )/ (2*a) | ||
+ | root2 = (+b + disc )/ (2*a) | ||
+ | print( "solutions: ", root1, root2 ) | ||
+ | except xxx: | ||
print( "You didn't enter 3 numbers" ) | print( "You didn't enter 3 numbers" ) | ||
− | except | + | except xxx: |
print( "Your inputs were not all numbers" ) | print( "Your inputs were not all numbers" ) | ||
− | except | + | except xxx: |
print( "Forgot commas between the numbers?" ) | print( "Forgot commas between the numbers?" ) | ||
− | except | + | except xxx: |
print( "No real roots, negative discriminant" ) | print( "No real roots, negative discriminant" ) | ||
+ | </source> | ||
+ | <br /> | ||
+ | * If you really want to be thorough and catch all kinds of exceptions, you could add a final '''except''' statement at the end of the list of except lines: | ||
+ | <br /> | ||
+ | ::<source lang="python"> | ||
except: | except: | ||
− | print( "Something went wrong | + | print( "Something went wrong" ) |
− | |||
</source> | </source> | ||
<br /> | <br /> | ||
+ | * By not specifying any error in this except clause, you indicate that *ALL* exceptions that do not trigger one of the exceptions above should be caught, and greeted with a "Something went wrong" message. | ||
+ | * Run your program, and when it prompts you for 3 numbers, type Control-C, which normally would stop a program by making it crash. See what this last except does with Control-C? | ||
+ | |||
+ | <!-- ========================================================================================= | ||
==Part 2: Exercise== | ==Part 2: Exercise== | ||
Line 189: | Line 237: | ||
* Repeat the same process for the other functions. | * Repeat the same process for the other functions. | ||
<br /> | <br /> | ||
+ | |||
+ | ======================================================================== --> | ||
+ | |||
=Classes and Objects= | =Classes and Objects= | ||
<br /> | <br /> | ||
Line 197: | Line 248: | ||
<br /> | <br /> | ||
::<source lang="python"> | ::<source lang="python"> | ||
− | # | + | # lab9_3.py |
# D. Thiebaut | # D. Thiebaut | ||
# Program for Week #9 | # Program for Week #9 | ||
Line 472: | Line 523: | ||
for i in range( len( words ) ): | for i in range( len( words ) ): | ||
print( "words[",i,"]=", words[i].strip(), end=", " ) | print( "words[",i,"]=", words[i].strip(), end=", " ) | ||
+ | |||
+ | # if words[2].find( "not" ) != -1: | ||
+ | # print( "might want to vaccinate this guy!" ) | ||
print() | print() | ||
Line 482: | Line 536: | ||
* This means that your program must | * This means that your program must | ||
::# extract each cat from a line of the file, | ::# extract each cat from a line of the file, | ||
− | ::# transform the string "vaccinated" in True, and "not vaccinated" in False (it | + | ::# transform the string "vaccinated" in True, and "not vaccinated" in False (You may want to uncomment the if statement in the program above, and run it to see how to detected vaccination!) |
− | ::# transform the string "tattooed" in True, and "not tattooed" in False (same comment), | + | ::# transform the string "tattooed" in True, and "not tattooed" in False (same comment as above), |
::# transform the string containing the age into an int, | ::# transform the string containing the age into an int, | ||
::# and store all this information into a Cat object. All the cats should be added to a list. | ::# and store all this information into a Cat object. All the cats should be added to a list. | ||
Line 520: | Line 574: | ||
Silky :==> Siamese, vaccinated, tattooed, 3 yrs old | Silky :==> Siamese, vaccinated, tattooed, 3 yrs old | ||
</source> | </source> | ||
+ | <br /> | ||
+ | <br /> | ||
+ | {| style="width:100%; background:silver" | ||
+ | |- | ||
+ | | | ||
+ | ==Challenge #4: Reading the Cat information from a CSV file== | ||
+ | |} | ||
+ | [[Image:QuestionMark8.jpg|right|120px]] | ||
+ | <br /> | ||
+ | Make your program output the cat information formatted as shown below. This will be the program you'll be submitting to Moodle in the next section. | ||
+ | <br /> | ||
+ | ;Example CSV file: | ||
+ | ::<source lang="text"> | ||
+ | Max, 21, vaccinated, not tattooed, stray | ||
+ | Toto, 3, not vaccinated, tattooed, stray | ||
+ | Garfield, 1, not vaccinated, not tattooed, Burmese | ||
+ | Bob, 4, not vaccinated, tattooed, Orange Tabby | ||
+ | Minou, 10, not vaccinated, not tattooed, stray | ||
+ | </source> | ||
+ | <br /> | ||
+ | ;Program output | ||
+ | <br /> | ||
+ | ::<source lang="text"> | ||
+ | Complete List: | ||
+ | Max :==> stray, vaccinated, not tattooed, 21 yrs old | ||
+ | Toto :==> stray, not vaccinated, tattooed, 3 yrs old | ||
+ | Garfield :==> Burmese, not vaccinated, not tattooed, 1 yrs old | ||
+ | Bob :==> Orange Tabby, not vaccinated, tattooed, 4 yrs old | ||
+ | Minou :==> stray, not vaccinated, not tattooed, 10 yrs old | ||
+ | |||
+ | Non-vaccinated cats: | ||
+ | Toto :==> stray, not vaccinated, tattooed, 3 yrs old | ||
+ | Garfield :==> Burmese, not vaccinated, not tattooed, 1 yrs old | ||
+ | Bob :==> Orange Tabby, not vaccinated, tattooed, 4 yrs old | ||
+ | Minou :==> stray, not vaccinated, not tattooed, 10 yrs old | ||
+ | |||
+ | Stray cats: | ||
+ | Max :==> stray, vaccinated, not tattooed, 21 yrs old | ||
+ | Toto :==> stray, not vaccinated, tattooed, 3 yrs old | ||
+ | Minou :==> stray, not vaccinated, not tattooed, 10 yrs old | ||
+ | |||
+ | Non-vaccinated cats 2 or older: | ||
+ | Toto :==> stray, not vaccinated, tattooed, 3 yrs old | ||
+ | Bob :==> Orange Tabby, not vaccinated, tattooed, 4 yrs old | ||
+ | Minou :==> stray, not vaccinated, not tattooed, 10 yrs old | ||
+ | |||
+ | Non-tattooed cats: | ||
+ | Max :==> stray, vaccinated, not tattooed, 21 yrs old | ||
+ | Garfield :==> Burmese, not vaccinated, not tattooed, 1 yrs old | ||
+ | Minou :==> stray, not vaccinated, not tattooed, 10 yrs old | ||
+ | |||
+ | Not vaccinated and tattooed cats: | ||
+ | Toto :==> stray, not vaccinated, tattooed, 3 yrs old | ||
+ | Bob :==> Orange Tabby, not vaccinated, tattooed, 4 yrs old | ||
+ | |||
+ | |||
+ | </source> | ||
+ | <br /> | ||
+ | <br /> | ||
<br /> | <br /> | ||
=Moodle Submission= | =Moodle Submission= | ||
<br /> | <br /> | ||
− | + | Submit your final lab9_3.py program to Moodle. Your program should prompt the user for the name of a CSV file that will contain a list of cats. | |
− | |||
− | |||
− | <tanbox>Make sure your program prints a blank line after getting the name of the file from the user! This blank line is used by | + | <tanbox>Make sure your program prints a blank line after getting the name of the file from the user! This blank line is used by the autograder to figure out where the output of your program starts. |
+ | </tanbox> | ||
<br /> | <br /> | ||
==Example== | ==Example== | ||
Line 553: | Line 665: | ||
File name? cats2.csv | File name? cats2.csv | ||
+ | Complete list: | ||
+ | Max :==> stray, vaccinated, not tattooed, 1 yrs old | ||
Black :==> stray, not vaccinated, tattooed, 3 yrs old | Black :==> stray, not vaccinated, tattooed, 3 yrs old | ||
− | + | etc... | |
− | |||
</source> | </source> | ||
<br /> | <br /> | ||
Line 727: | Line 840: | ||
--> | --> | ||
− | + | </onlydft> | |
<!-- ============================================================= --> | <!-- ============================================================= --> | ||
<!-- ============================================================= --> | <!-- ============================================================= --> | ||
Line 733: | Line 846: | ||
<!-- ============================================================= --> | <!-- ============================================================= --> | ||
− | <showafterdate after=" | + | <showafterdate after="20180409 12:00" before="20180601 00:00"> |
=Solution Programs= | =Solution Programs= | ||
==Part 1 == | ==Part 1 == |
Latest revision as of 13:59, 1 June 2018
D. Thiebaut (talk) 09:54, 1 April 2018 (EDT)
<showafterdate after="20180409 12:00" before="20180601 00:00">
Solution Programs
Part 1
# lab9 programs
# D. Thiebaut
# getInput: returns an integer larger
# than 0. Expected to be robust
def getInput():
while True:
x = int( input( "Enter an integer greater than 0: " ) )
if x <= 0:
print( "Invalid entry. Try again!" )
else:
return x
# betterGetInput: returns an integer larger
# than 0. Expected to be robust
def betterGetInput():
# repeat forever...
while True:
# try to get an int
try:
x = int( input( "Enter an integer greater than 0: " ) )
except ValueError:
# the user must have entered something other than an int
print( "Invalid entry. Not an integer. Try again!" )
continue
# There was no errors. See if the number is negative
if x <= 0:
print( "You entered a negative number. Try again!" )
else:
return x
def main1():
num = betterGetInput()
print( "You have entered", num )
# =======================================================================
def example1():
print( "You will need to enter 3 pairs of ints..." )
while True:
try:
x = int( input( "enter a number: " ) )
y = int( input( "enter another number: " ) )
print( x, '/', y, '=', x/y )
break
except ZeroDivisionError:
print( "Can't divide by 0!" )
except ValueError:
print( "That doesn't look like a number!" )
except:
print( "something unexpected happend!" )
def example2( L ):
print( "\n\nExample 2" )
sum = 0
for i in range( len( L ) ):
try:
sum += L[i]
except TypeError:
continue
print( "sum of items in ", L, "=", sum )
def printUpperFile( fileName ):
try:
file = open( fileName, "r" )
except FileNotFoundError:
print( "***Error*** File", fileName, "not found!" )
return
# if we're here, the file is found and open
for line in file:
print( line.upper() )
file.close()
def createTextFile( fileName ):
file = open( fileName, "w" )
file.write( "Welcome\nto\nCSC111\nIntroduction\nto\nComp.\nSci.\n" )
file.close()
def main2():
createTextFile( "csc111.txt" )
example1()
L = [ 10, 3, 5, 6, 9, 3 ]
example2( L )
#example2( [ 10, 3, 5, 6, "NA", 3 ] )
printUpperFile( "csc111.txt" )
#printUpperFile( "csc1111.txt" )
main2()
Part 2
# cats1.py
# D. Thiebaut
# Program for Week #9
# Define a Cat class, and
# use it to create a collection of
# cats.
class Cat:
"""a class that implements a cat and its
information. Name, breed, vaccinated,
tattooed, and age."""
def __init__( self, na, brd, vacc, ag, tat ):
"""constructor. Builds a cat with all its information"""
self.name = na
self.breed = brd
self.vaccinated = vacc
self.age = ag
self.tattooed = tat
def isTattooed( self ):
"""returns True if cat is tattooed, False otherwise"""
return self.tattooed
def isVaccinated( self ):
"""returns True if cat is vaccinated, False otherwise"""
return self.vaccinated
def getAge( self ):
"""returns cat's age"""
return self.age
def getName( self ):
"""returns name of cat"""
return self.name
def getBreed( self ):
return self.breed
def __str__( self ):
"""default string representation of cat"""
vacc = "vaccinated"
if not self.vaccinated:
vacc = "not vaccinated"
tatt = "tattooed"
if not self.tattooed:
tatt = "not tattooed"
return "{0:20}:==> {1:1}, {2:1}, {3:1}, {4:1} yrs old".format(
self.name, self.breed, vacc, tatt, self.age )
def readCatCSV( fileName ):
""" reads the CSV file and puts all the cats
in a list of Cat objects"""
# get the lines from the CSV file
file = open( fileName, "r" )
lines = file.readlines()
file.close()
# create an empty list of cats
cats = []
# get one line at a time
for line in lines:
# split a line in words
fields = line.split( ", " )
# skip lines that do not have 5 fields
if len( fields ) != 5:
continue
# get 5 fields into 5 different variables
name, age, vac, tat, breed = fields
breed = breed.strip()
# transform "vaccinated" or "not vaccinated" in True or False
if vac.lower().find( "not " )==-1:
vac = True
else:
vac = False
# transform "tattooed" or "not tattooed" in True or False
if tat.lower().find( "not " )==-1:
tat = True
else:
tat = False
# add a new cat to the list
cats.append( Cat( name, breed, vac, int(age), tat ) )
# done with the lines. Return the cat list
return cats
def main():
""" main program. Creates a list of cats and displays
groups sharing the same property.
Minou, 3, vac, stray, tat
Max, 1, not-vac, Burmese, tat
Gizmo, 2, vac, Bengal, tat
Garfield, 4, not-vac, Orange Tabby
"""
cats = readCatCSV( input( "File name? " ) )
"""
cat = Cat( "Minou", "stray", True, 3, True)
cats.append( cat )
cats.append( Cat( "Max", "Burmese", False, 1, True ) )
cats.append( Cat( "Gizmo", "Bengal", True, 2, True ) )
cats.append( Cat( "Garfield", "Orange Tabby", False, 4, False ) )
"""
# print the list of all the cats
print( "\nComplete List:" )
for cat in cats:
print( cat )
print( "\nNon-vaccinated cats:" )
for cat in cats:
if cat.isVaccinated()==False:
print( cat )
print( "\nStray cats:" )
for cat in cats:
if cat.getBreed().lower() == "stray":
print( cat )
print( "\nNon-vaccinated cats 2 or older:" )
for cat in cats:
if cat.isVaccinated()==False and cat.getAge() >= 2:
print( cat )
print( "\nNon-tattooed cats:" )
for cat in cats:
if cat.isTattooed()==False:
print( cat )
print( "\nVaccinated and tattooed cats:" )
for cat in cats:
if cat.isVaccinated() and cat.isTattooed():
print( cat )
def lab9Solution():
"""prompts user for file name, and outputs
cats that are not vaccinated, and 2 years or older"""
cats = readCatCSV( input( "File name? " ) )
print()
for cat in cats:
if cat.isVaccinated()==False and cat.getAge() >= 2:
print( cat )
#main()
lab9Solution()
</showafterdate>