9.15. Exercises

1. For each word in the list verbs, add an -ing ending. Overwrite the old list so that verbs has the same words with ing at the end of each one.

   verbs = ["kayak", "cry", "walk", "eat", "drink", "fly"] ===== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testSeven(self): self.assertEqual(verbs, ['kayaking', 'crying', 'walking', 'eating', 'drinking', 'flying'], "Testing that verbs is assigned to correct values.") myTests().main()

2. In XYZ University, upper level math classes are numbered 300 and up. Upper level English classes are numbered 200 and up. Upper level Psychology classes are 400 and up. Create two lists, upper and lower. Assign each course in classes to the correct list, upper or lower. HINT: remember, you can convert some strings to different types!

   classes = ["MATH 150", "PSYCH 111", "PSYCH 313", "PSYCH 412", "MATH 300", "MATH 404", "MATH 206", "ENG 100", "ENG 103", "ENG 201", "PSYCH 508", "ENG 220", "ENG 125", "ENG 124"] ===== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testEightA(self): self.assertEqual(upper, ['PSYCH 412', 'MATH 300', 'MATH 404', 'ENG 201', 'PSYCH 508', 'ENG 220'], "Testing that the upper list exists and contains the correct elements.") def testEightB(self): self.assertEqual(lower, ['MATH 150', 'PSYCH 111', 'PSYCH 313', 'MATH 206', 'ENG 100', 'ENG 103', 'ENG 125', 'ENG 124'], "Testing that the lower list exists and contains the correct elements.") myTests().main()

3. Starting with the list myList = [76, 92.3, ‘hello’, True, 4, 76], write Python statements to do the following:

   1. Append “apple” and 76 to the list.

   2. Insert the value “cat” at position 3.

   3. Insert the value 99 at the start of the list.

   4. Find the index of “hello”.

   5. Count the number of 76s in the list.

   6. Remove the first occurrence of 76 from the list.

   7. Remove True from the list using pop and index.

   myList = [76, 92.3, 'hello', True, 4, 76] # Your code here

   myList = [76, 92.3, 'hello', True, 4, 76] myList.append("apple") # a myList.append(76) # a myList.insert(3, "cat") # b myList.insert(0, 99) # c print(myList.index("hello")) # d print(myList.count(76)) # e myList.remove(76) # f myList.pop(myList.index(True)) # g print (myList)

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4. The module keyword determines if a string is a keyword. e.g. keyword.iskeyword(s) where s is a string will return either True or False, depending on whether or not the string is a Python keyword. Import the keyword module and test to see whether each of the words in list test are keywords. Save the respective answers in a list, keyword_test.

   test = ["else", "integer", "except", "elif"] keyword_test = [] ===== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testOneA(self): self.assertEqual(keyword_test, [True, False, True, True], "Testing that keyword_test is correct and p1 assigned to correct values") myTests().main()

5. The string module provides sequences of various types of Python characters. It has an attribute called digits that produces the string ‘0123456789’. Import the module and assign this string to the variable nums. Below, we have provided a list of characters called chars. Using nums and chars, produce a list called is_num that consists of tuples. The first element of each tuple should be the character from chars, and the second element should be a Boolean that reflects whether or not it is a Python digit.

   chars = ['h', '1', 'C', 'i', '9', 'True', '3.1', '8', 'F', '4', 'j'] ===== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testOneA(self): self.assertEqual(is_num, [('h', False), ('1', True), ('C', False), ('i', False), ('9', True), ('True', False), ('3.1', False), ('8', True), ('F', False), ('4', True), ('j', False)], "Testing that is_num was created correctly.") myTests().main()

9.15.1. Contributed Exercises

The transpose of a matrix is flipped along its diagonal. E.g., an input matrix that looks like

\[\begin{split}\left[\begin{array}{ccc} 0 & 1 & 2\\ 3 & 4 & 5 \end{array}\right]\end{split}\]

and will have a list representation of

[[0, 1, 2], [3, 4, 5]]

Its transpose will be

\[\begin{split}\left[\begin{array}{ccc} 0 & 3\\ 1 & 4\\ 2 & 5 \end{array}\right]\end{split}\]

and will have a list representation of

[[0, 3], [1, 4], [2, 5]]

Compute the transpose of mat_a and mat_b below and store them in mat_at and mat_bt respectively.

mat_a = [[15, 1, 56], [98, 86, 10]] mat_b = [[66, 53, 77, 65], [79, 63, 85, 41], [36, 88, 28, 22], [6, 65, 20, 89]] # create the transposed matrix with all zeros mat_at = [] for j in range(len(mat_a[0])): mat_at.append([0]*len(mat_a)) ==== from unittest.gui import TestCaseGui import re import math class myTests(TestCaseGui): def testOne(self): output = self.getOutput().split('\n') editor = self.getEditorText().split('\n') float_re = r'[-+]?(\d+(\.\d*)?|\.\d+)([eE][-+]?\d+)?' _mat_a = [[15, 1, 56], [98, 86, 10]] _mat_b = [[66, 53, 77, 65], [79, 63, 85, 41], [36, 88, 28, 22], [6, 65, 20, 89]] _mat_at = [] for j in range(len(_mat_a[0])): _mat_at.append([0]*len(_mat_a)) for i in range(len(_mat_a)): for j in range(len(_mat_a[i])): _mat_at[j][i] = _mat_a[i][j] _mat_bt = [] for j in range(len(_mat_b[0])): _mat_bt.append([0]*len(_mat_b)) for i in range(len(_mat_b)): for j in range(len(_mat_b[i])): _mat_bt[j][i] = _mat_b[i][j] self.assertEqual(mat_at, _mat_at, 'Checking mat_at') self.assertEqual(mat_bt, _mat_bt, 'Checking mat_bt') # hardcode check float_re = r'[-+]?(\d+(\.\d*)?|\.\d+)([eE][-+]?\d+)?' print_float_re = r'print\( *'+float_re+' *\)' self.assertFalse(re.search(print_float_re, self.getEditorText()), 'Checking for hardcoding') 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)==2, 'Checking for-statements') myTests().main()

Create a new list called sqrts that contains the square root of each number in the list numbers. Your solution should work for any number of elements in the list.

First, create an empty list, then add each value using append().

numbers = [71, 96, 88, 76, 39, 34, 17, 88, 40, 69, 51, 23, 84, 74, 14, 84, 20, 63, 37] ==== from unittest.gui import TestCaseGui import re import math class myTests(TestCaseGui): def testOne(self): output = self.getOutput().split('\n') editor = self.getEditorText().split('\n') float_re = r'[-+]?(\d+(\.\d*)?|\.\d+)([eE][-+]?\d+)?' _numbers = [71, 96, 88, 76, 39, 34, 17, 88, 40, 69, 51, 23, 84, 74, 14, 84, 20, 63, 37] _sqrts = [] for i in range(len(numbers)): _sqrts.append(numbers[i]**0.5) self.assertEqual(len(numbers), len(_numbers), 'Checking number of elements') for number, _number in zip(numbers, _numbers): self.assertEqual(number, _number, 'Checking answer') self.assertTrue(re.search(r'sqrts *\. *append *\(', self.getEditorText()), 'Checking for append') # hardcode check float_re = r'[-+]?(\d+(\.\d*)?|\.\d+)([eE][-+]?\d+)?' print_float_re = r'print\( *'+float_re+' *\)' self.assertFalse(re.search(print_float_re, self.getEditorText()), 'Checking for hardcoding') 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)>=1 and len(inner_loops)==0, 'Checking for-statements') myTests().main()

Pig latin is a language game or argot. The rules are

1. All consonants at the start of the string are moved to the end. (Treat ‘y’ is a vowel here.)

2. An ‘a’ is added to the end of the string.

For example, ‘string’ becomes ‘ingstra’.

Copy the list english into a new list called pig_latin and translate each word into pig latin. You may use + to create new strings but do not use append or + to build the list pig_latin.

english = ['computational', 'physics', 'is', 'awesome'] ==== from unittest.gui import TestCaseGui import re import math class myTests(TestCaseGui): def testOne(self): output = self.getOutput().split('\n') editor = self.getEditorText().split('\n') float_re = r'[-+]?(\d+(\.\d*)?|\.\d+)([eE][-+]?\d+)?' _english = ['computational', 'physics', 'is', 'awesome'] _pig_latin = _english[:] for iword in range(len(_pig_latin)): for letter in _pig_latin[iword]: if letter not in 'aeiouy': _pig_latin[iword] = _pig_latin[iword][1:]+letter else: break _pig_latin[iword] = _pig_latin[iword]+'a' self.assertEqual(english, _english, 'Checking that the original list has not changed') self.assertEqual(pig_latin, _pig_latin, 'Checking the new list') # hardcode check float_re = r'[-+]?(\d+(\.\d*)?|\.\d+)([eE][-+]?\d+)?' print_float_re = r'print\( *'+float_re+' *\)' self.assertFalse(re.search(print_float_re, self.getEditorText()), 'Checking for hardcoding') self.assertFalse(re.search(r'append', self.getEditorText()), 'Checking for hardcoding') self.assertTrue(re.search(r'\[.*:.*\]', self.getEditorText()), 'Checking for hardcoding') 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)==1 and len(inner_loops)==1, 'Checking for-statements') myTests().main()

Create an alias named cities that points to the same list as the existing municipalities variable. Then, create a list named towns that is a clone of cities. towns and cities should be independent objects and not aliases.

Once you have created the lists, change “Blacksville” in municipalities to “Town of Blacksville”. Print out the content of element 4 in each list.

municipalities = ['Morgantown', 'Star City', 'Westover', 'Granville', 'Blacksville'] ==== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testOne(self): self.assertEqual(id(cities),id(municipalities),"cities and municipalities must point to the same list") def testTwo(self): self.assertNotEqual(id(cities),id(towns),"cities and towns must not point to the same list") self.assertEqual(cities[0],towns[0],"cities and towns should have the same municipalities listed") def testThree(self): self.assertEqual(municipalities[4],"Town of Blacksville","Blacksville should be changed to Town of Blacksville") myTests().main()

Consider the code given to you below. It iterates through a list of 5 integers, and appends them to a list. Run the code first and see the result. Now, by only modifying line 3 change the code to instead of just adding an element to the list, it adds each number multiplied by two.

my_list = [] for num in range(1, 6): my_list.append(num) print(my_list) ==== from unittest.gui import TestCaseGui import re class myTests(TestCaseGui): def testOne(self): self.assertEqual('[2, 4, 6, 8, 10]\n', self.getOutput(), 'Checking output.') myTests().main()

Q-1: What will be the value of a after the following code has executed?

a = ["holiday", "celebrate!"]
b = a
b.append("company")

• ["holiday", "celebrate", "company"]
• This is true. It is called aliasing (Section 9.5).
• Nothing. There's an error.
• There is no error in this code. Please check Section 9.5 (Aliasing) to understand why not.
• ["holiday", "celebrate"]
• That's incorrect. What we used here is something called aliasing. Both a and b variables refer to the same list. So either you append to a or b, you append to the same list.

You are supplied with a string s below. Using python and not hard coding…Remove white space from the beginning and end, make the string lower case and replace all the words ‘cat’ with ‘dog’. This new string should be saved as newS. The final string should look like newS=’the dog ate the dog food, it was yummy!’

s=' The cat ate the dog food, it was YUMMY! ' ==== from unittest.gui import TestCaseGui import re class myTests(TestCaseGui): def testOne(self): self.assertTrue('newS' in globals(),'newS has been created') self.assertTrue(newS==s.strip().lower().replace('cat','dog'), 'Correct string created') self.assertTrue('the dog ate the dog food, it was yummy!' not in self.getEditorText(), 'The string was not hard coded') myTests().main()

Write a program that will accept words from a user, one at a time, until the user types the word ‘quit’. Start with an empty list, and append each new word to that list. After the user types quit, print out the list of words.

First copy your code from the previous problem. This problem will again ask the user for a bunch of words and print out the words. Then it will sort the words using the bubble sort technique we learned in class (no other sort methods allowed!) Print out the sorted list.

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