7.14. Exercises

4. In Robert McCloskey’s book Make Way for Ducklings, the names of the ducklings are Jack, Kack, Lack, Mack, Nack, Ouack, Pack, and Quack. This loop tries to output these names in order.

   Of course, that’s not quite right because Ouack and Quack are misspelled. Can you fix it?

   prefixes = "JKLMNOPQ" suffix = "ack" for p in prefixes: print(p + suffix) ==== from unittest.gui import TestCaseGui import re class myTests(TestCaseGui): def testOne(self): # check the answer self.assertTrue(re.search('Jack', self.getOutput()), 'Checking answer.') self.assertTrue(re.search('Kack', self.getOutput()), 'Checking answer.') self.assertTrue(re.search('Lack', self.getOutput()), 'Checking answer.') self.assertTrue(re.search('Mack', self.getOutput()), 'Checking answer.') self.assertTrue(re.search('Nack', self.getOutput()), 'Checking answer.') self.assertTrue(re.search('Ouack', self.getOutput()), 'Checking answer.') self.assertTrue(re.search('Pack', self.getOutput()), 'Checking answer.') self.assertTrue(re.search('Quack', self.getOutput()), 'Checking answer.') # hardcode check prefixes = ['J','K','L','M','N','Ou','P','Qu'] self.assertFalse(re.search(r'('+'|'.join([p+suffix for p in prefixes])+r')', self.getEditorText()), 'Checking for hardcoding') myTests().main()

5. Get the user to enter some text and store it in a variable called user_input then print it out in reverse order.

   ==== from unittest.gui import TestCaseGui import re class myTests(TestCaseGui): def testOne(self): self.assertTrue(re.search(user_input[::-1], self.getOutput()), 'Checking answer.') myTests().main()

6. Write a program that uses a for loop to print

   One of the months of the year is January

   One of the months of the year is February

   One of the months of the year is March

   etc …

   for amonth in ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'November', 'December']: print("One of the months of the year is", amonth)

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7. Assume you have a list of numbers 12, 10, 32, 3, 66, 17, 42, 99, 20

   1. Write a loop that prints each of the numbers on a new line.

   2. Write a loop that prints each number and its square on a new line.

   ==== from unittest.gui import TestCaseGui import re class myTests(TestCaseGui): def testOne(self): _seq = [12, 10, 32, 3, 66, 17, 42, 99, 20] _seq.extend(["{:d} +{:d}".format(number, number**2) for number in _seq]) _seq = [str(s) for s in _seq] output = self.getOutput().split('\n') for expected, line in zip(_seq,output): self.assertTrue(re.search(expected, line), 'Checking line') outer_loops = re.findall(r'^(for[ (].* in.*: *)$', self.getEditorText(), re.M) inner_loops = re.findall(r'^( +for[ (].* in.*: *)$', self.getEditorText(), re.M) self.assertTrue(len(outer_loops)==2 and len(inner_loops)>=0, 'Checking for-statements') myTests().main()

8. Write a program that asks the user for the number of sides, the length of the side, the color, and the fill color of a regular polygon. The program should draw the polygon and then fill it in.

9. A drunk pirate makes a random turn and then takes 100 steps forward, makes another random turn, takes another 100 steps, turns another random amount, etc. A social science student records the angle of each turn before the next 100 steps are taken. Her experimental data is 160, -43, 270, -97, -43, 200, -940, 17, -86. (Positive angles are counter-clockwise.) Use a turtle to draw the path taken by our drunk friend. After the pirate is done walking, print the current heading. Assume that the turtle originally has a heading of 0 and accumulate the changes in heading to print out the final. Your solution should work for any sequence of experimental data.

   import turtle wn = turtle.Screen() lovelace = turtle.Turtle() # move the turtle forward a little so that the whole path fits on the screen lovelace.penup() lovelace.forward(60) # now draw the drunk pirate's path lovelace.pendown() current_heading = 0 for angle in [160, -43, 270, -97, -43, 200, -940, 17, -86]: # we use .left() so that positive angles are counter-clockwise # and negative angles are clockwise current_heading = (current_heading + angle) % 360 lovelace.left(angle) lovelace.forward(100) # the .heading() method gives us the turtle's current heading in degrees print("The pirate's final heading was", current_heading) wn.exitonclick()

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10. Write a program that will go through a list of temperatures and print them out to the user.

            temperatures = [-3, 78, 95, 28, 56, 42, 56, 81, -10, -]
    ====
    for temp in temperatures:
    ====
        print("The weather outside is: " + str(temp))
            

11. Write a program that will print out a greeting to each student in the list. This list should also keep track of how many students have been greeted and note that each time a new student has been greeted.

            students = ["Jay", "Stacy", "Iman", "Trisha", "Ahmed", "Daniel", "Shadae", "Tosin", "Charlotte"]
    ====
    num_students = 0
    ====
    for student in students:
    ====
        print("Welcome to class, " + student)
    ====
        num_students += 1
        print(str(num_students) + "student(s) have entered the classroom")
            

7.14.1. Contributed Exercises

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