5.10. Exercises: Booleans and Conditionals

If your teacher added you to a Trinket course, complete the exercises there.

Otherwise, use the links below to code in your own free Replit or Trinket account.

5.10.1. Part A: Basic Selection

If you are NOT assigned to a Trinket course, follow one of these links for the Part A starter code:

1. repl.it starter

2. Trinket starter

5.10.1.1. if Only

Prompt the user to enter a word and store the result in user_entry:

user_entry = input('Enter a word: ')

1. Use a conditional to check the length of the word. If longer than 5 characters, print, "___ is longer than 5 characters." Otherwise, print nothing. (Note: Fill in the blank with the value of user_entry).

5.10.1.2. Binary Selection

Prompt the user to enter a number:

num_entry = int(input('Enter a number larger than 100: '))

2. Check if num_entry is 100 or larger. If so, print, "Valid entry!" Else print, "Number too small."

The in keyword can be used as another comparison operator.

Example

print('ana' in 'banana')
print('z' in 'apple')

Console Output

True
False

The string ana is present within banana, while there is no z character within apple.

3. Prompt the user to enter a lowercase letter. Use the in operator to check if the letter is a vowel (e.g. in the string aeiou). If so, print, "___ is a vowel." Else, print, "___ is NOT a vowel."

4. What happens if the user enters a capital letter instead of lowercase? Refactor your code for problem 3 so that it works for both capital and lowercase vowels!

Check your solutions.

5.10.2. Part B: Logical Operators

Use the logical and, or, and not operators in the following exercises. Once again, if you are not assigned Trinket course, access the Part B starter code here: repl.it or Trinket.

1. Given an integer, check to see if the number is even and divisible by 5. Print an appropriate message depending on the result.

2. Given a string, print, "___ is a really long word!" if the string is longer than 9 characters and does NOT contain a space. Otherwise, print, "___ is either short, or it contains multiple words." Fill in the blank with the original string.

3. Refactor the following code to check if letter is NOT in the string 'BCDFGHJKLMNPQRSTVWXYZ' or is a lowercase vowel. How does making this change affect the if/else code blocks?

   letter = 'A'
   cap_consonants = 'BCDFGHJKLMNPQRSTVWXYZ'
   vowels = 'aeiou'
   
   if letter in cap_consonants or letter in vowels:
      print("'" + letter + "'", "is either a lowercase vowel OR a capital consonant.")
   else:
      print("Pick a capital consonant or a lowercase vowel.")
   

4. If num = 5, indicate whether each of following expressions returns True or False.

   num >= 0 and num*2 <= 50 and num%2 == 0
   num >= 0 or num*2 <= 50 or num%2 == 0
   num >= 0 and num*2 <= 50 or num%2 == 0
   num >= 0 or num*2 <= 50 and num%2 == 0
   not num < 0 and num%3 != 0
   not (num%3 == 0 or num*4 >= 20)
   

Check your solutions.

5.10.3. Part C: Chained Conditionals

Use this starter code for Parts C and D: repl.it or Trinket.

1. For if/elif/else statements, the order of the checks is important. The following code should determine if a number is divisible by 2, 3, both or neither, but as written it does not behave as we want. Rearrange the order of the if, elif, and else code blocks as needed to give the desired results.

   num = 6 # Try the values 10, 15, and 7 as well.
   
   if num%2 == 0:
      print(num, "is divisible by 2.")
   elif num%3 == 0:
      print(num, "is divisible by 3.")
   elif num%2 == 0 and num%3 == 0:
      print(num, "is divisible by 2 and 3.")
   else:
      print(num, "is NOT divisible by 2 or 3.")
   

   For num = 6, the output should be '6 is divisible by 2 and 3.'

2. Given the score on an exam, use a chained conditional to assign it the proper letter grade. Assume a standard 10-point range for each letter (A = 100 - 90, B = 89 - 80, C = 79 - 70, etc.). Print the results as ___% = ___. Fill in the first blank with the score and the second blank with the letter grade.

3. Write code to help you pick an activity based on the current weather. Consider two variables, one for temperature (hot or cold) and one for how wet it is (rainy or dry). If the weather is hot and rainy, your code should tell you to watch Netflix. For hot and dry conditions, it should tell you to go swimming. If cold and rainy, it should tell you to get under a blanket and read. If it is cold and dry, it should tell you to hang out with a friend.

Check your solutions.

5.10.4. Part D: Nested Conditionals

4. Ask the user for their lunch selection - burger or salad. If they choose salad, ask them for a dressing option (ranch or italian). If they choose burger ask them if they want cheese (yes or no). Print out their final order.

5. Each option has a different price. Add a cost variable to your code and calculate the bill for the lunch order. Include this in the print statement.

6. Assume you want to add a drink question for the customer. Where would be the BEST place to ask this question? EXPLAIN your reasoning for your choice.

   1. Inside the nested statements before the cheese/dressing questions.

   2. Inside the nested statements after the cheese/dressing question.

   3. As a separate conditional outside of the nested statements.

Check your solutions.