Homework 8: For Loop Homework

Due: Monday, October 27

Consider the following exercises in CodingBat. Be sure to share your progress with me, by going to “prefs” and entering your instructor’s email address (seme@hendrix.edu or yorgey@hendrix.edu) in the “Teacher Share” box.

• string_splosion
• string_bits
• array_count9
• array123
• string_match

For each of the following excercises:

1. Predict: First, complete the exercise without using the Python interpreter. (You are welcome to refer to your notes or textbook, read Python documentation, look at examples from class, etc.; just don’t actually run any code.) Trace the execution of the code, keeping track of the function stack, all variables, and any output produced.

2. Check: Run the code. Does the actual output agree with what you wrote down in step 1?

3. Evaluate: If your answer to part 1 was different than the actual output, keep experimenting with it, consult the textbook or Python documentation, ask a friend or TA or professor, etc. until you can explain why the code works the way it does and what your misunderstanding(s) were in part 1. (You do not need to do anything for step 3 if the output agrees exactly with what you wrote in step 1.)

4. Write, using a `for’ loop, a function which given a list of integers, return a count of the number of even integers in the list

5. What is printed by the code below?

    s = 'abcdef'
    v = 'aeiou'
    count = 0
    for char in s:
        if char in v:
            count += 1
    print(count)

1. What is the value of new_list after the code below runs?

    lst = [5, 1, 4, 7, 8, 10, 2]
    new_list = []
    for item in lst:
        if item % 2 == 0:
            new_list.append(item // 2)
        else:
            new_list.append(item)