Chapter 7 Exercises¶

1. Complete lines 1 and 2 below to create the code to add up all the numbers from 1 to 5 and print the sum.

   sum = ?? things_to_add = ?? for number in things_to_add: sum = sum + number print(sum)

2. Fix the errors in the code so that it prints the sum of all the numbers 1 to 10.

   sum = 0 num_list = range(1,10) for number in num_list: sum = number print(sum)

3. Fill in the missing values in the function sum_list so that it returns the sum of all the numbers in the parameter num_list. Create a test list and call sum_list passing it your list.

   def sum_list(num_list): total = ?? # Start with additive identity for n in ??: # Loop through each number ?? = ?? + ?? # Accumlate the total return ?? my_nums = ?? # Create a list of numbers print(sum_list(??)) # Print the call result to test

4. Fill in the missing code on lines 3 and 4 to loop through the list of numbers and calculate the product. Add a line at the end to print the value in product.

   product = 1 # Start with the multiplicative identity numbers = [1, 2, 3, 4, 5] for ?? in numbers: product = product * ?? ?? # Print the result

5. Fix the errors in the code so that it prints the product of every 5th number between 5 and 25, inclusive. So, the product of 5, 10, 15, …, 25. It should print the value 375000 if you have done everything correctly.

   product = 0 numbers = len(4, 25, 5) for number in numbers: product = product + number print(product)

6. Fix the errors in the code so that it prints the sum of all the odd numbers 1 through 20.

   sum = 1 numbers = range(1, 21, 1) for numbers in number: sum = sum + number print(sum)

7. Modify the code below to create a function that calculates the product of a list of numbers and returns it. Have the function take a list of numbers as a parameter. Call the function to test it and print the result of calling the function.

   product = 1 # Start out with 1 numbers = [1, 2, 3, 4, 5] for number in numbers: product = product * number print(product)

8. Fix the error in the code so that it takes each string in the list and prints out the sentence “I like to eat pizza”.

   a_string = "" a_list = ["I", "like", "to", "eat", "pizza"] for word in a_list: a_string = word print(a_string)

9. Fill in the code below on lines 2, 5, and 10 to correctly add up and print the sum of all the even numbers from 0 to 10 (inclusive).

   # Step 1: Initialize accumulator sum = ?? # Start with nothing (addition identity value) # Step 2: Get data numbers = range(??) # Step 3: Loop through the data for number in numbers: # Step 4: Accumulate sum = sum + ?? # Step 5: Display result print(sum)

10. Write code that prints the square of each number 1 through 10 in the format “1 * 1 = 1”, etc.

11. The code below sums the even numbers from 0 to 20 inclusive. Turn it into a function sum_evens(to_num) that calculates the sum of the even numbers from 0 to the value of to_num passed to the function. Return the sum from the function. Call the function inside print to see the result.

    # Step 1: Initialize accumulator sum = 0 # Start out with nothing # Step 2: Get data numbers = range(0, 21, 2) # Step 3: Loop through the data for number in numbers: # Step 4: Accumulate sum = sum + number # Step 5: Process result print(sum)

12. The factorial of a positive integer n is the product of all the integers from n down to 1.

    Complete the function below that returns the factorial of an integer passed to it and print the result of calling the function.

    def factorial(n): fact = ?? # Set fact to passed value for i in range(??, ??, -1): # Count down from n to 1 fact = ?? * ?? # Accumulate the product return ?? ?? # Call and print to test

13. Fix the code below to correctly calculate and return the product of all of the even numbers from 10 to 20.

    # Step 1: Initialize accumulator product = 0 # initialize product to multiplicative identity # Step 2: Get data numbers = range(10, 20, 2) # Step 3: Loop through the data for number in numbers: # Step 4: Accumulate product = product + number # Step 5: Process result print(product)

14. Use your solution to the previous exerice to complete the function below to calculate and return the sum of all of the even numbers from from_num to to_num inclusive. Calling sum_evens(6, 10) should return 24. Print the result of calling the function to test it.

    def sum_evens(from_num, to_num): # Step 1: Initialize accumulator # Step 2: Get data numbers = range(??, ??, 2) # Step 3: Loop through the data for number in numbers: # Step 4: Accumulate product = product * number # Step 5: Return result return ?? # Step 6: Print the result of calling the function print(??)

15. Create a list of all odd numbers from 1 to 20 and find the average. Then create a list of numbers from 1 to 100 using the average as the increment and print the product of those numbers.

16. Create a procedure to calculate and return the sum of all of the odd numbers from 1 to a passed last number (inclusive). Call the function to test and it print the result.

17. Complete the code for a function that takes a list of letters and combines them into a word. It should print “Hi”.

    def letter_combiner(??): temp_string = ?? for ?? in letter_list: temp_string = temp_string + letter return ?? a_list = ["H", "i"] print(letter_combiner(??))

18. Create a function to calculate and return the product of all of the even numbers from 2 to the passed end number (inclusive). Be sure to call the function to test it and print the result.

19. Write a function that takes two inputs, a start and stop for a range (inclusive). Find the product and the sum of all the numbers and return the average between those two numbers. make a call to the function where you print the result

20. Write a function that will take a list of numbers and return the average. Remember that the average is the sum of all of the numbers in the list divided by the number of items in the list. You can get the length of a list using the len(list) function.

21. Create a function named who_knows_why that takes one integer parameter, num, and gets a list of all the odd numbers in range(num) and all the even numbers in range(num), finds the product of all the odd numbers, the sum of all the even numbers, and then returns the difference of the product by the sum divided by the average of the two. Call the function and print the result.