Comp 115 Test 3 Study Guide

I tried my best to list the topics for the exam but I may have forgotten one or two. Your default assumption should be that if I covered it in class before files, it is fair game for the exam.

I will add practice problems as I find new interesting questions, so come back to this page every few days, more practice problems may have appeared.

In addition to all concepts from Test 2,

Lists

• operators on lists
• Accessing specific characters and slices, in particular, difference between accessing an element and doing a slice that includes only one element
• Differences between lists and strings
• List methods, what they look like, how to use them (you do not need to remember all of them, but if I describe one to you, you should be able to use it)

Repetition

• Syntax for the while loop and for loop
• Interactive loop, sentinel loop and counting loop, and how to use them to make a loop end at the desired time
• Accumulator pattern and how to use it to make the loop execute a simple task
• Be able to keep track of values of variables during the execution of a loop
• Be able to use loops to solve simple problems

Practice Problems

1. Finish any lab exercises that you did not have time to complete during lab time. Remember, I added a whole page of exercise for the week of Fall break during which we did not have lab.
2. Suppose that the assignment myList = ["fish", 3, 5.0, 1729, [7,8,9], 10, 39, 67] was just executed. What value would Python give to each of the following expressions:
   • myList[0]
   • myList[4]
   • myList[2:6]
   • myList[0:1]
   • myList[1:7:2]
   • myList[0][3]
   • myList[4][::2]
   • myList[:3:-3]
   Find a slice of the list in myList that would evaluate to the following value:
   • [3, 5.0, 1729]
   • [8,9]
   • [39]
   • "ish"
   • [10, [7,8,9], 1729]
3. Determine what would be printed by each of the following pieces of code:
   1. Assume the user enters the number 30 while running the following:

        myList = [5, 17, 45, 30, 29, 18]
        lookFor = int(input("Enter a number: "))
        i = 0
        while i < len(myList) and myList[i] != lookFor:
            i = i + 1
        print(i)

   2. What would be printed by the program of the previous question if the user entered 19.

   3.   for i in range(5):
            print("*"*i)

   4.   for i in range(5):
            print("{0:_>5}".format("*"*i))

   5.   myList = [1,2,3,4,5]
        for i in range(len(myList)):
            if myList[i] == 4:
                myList[i] = 1729
        print(myList)

   6.   currentValue = 2
        while currentValue < 100:
            print(currentValue)
            currentValue = 2 * currentValue + 5
        print("DONE")