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.

If you want to see the short video I will record about the test, click here (video is now available!).

In addition to all concepts from Test 3,

Lists

• Differences between lists and strings, especially about memory representation and its effect on function that have lists as input parameters and stack diagrams
• Understand the difference between a function that modifies a list it is given as an input parameter and a function that returns a new list and leaves the input list unmodified.

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

Files

(Note: questions about files will not be too hard, I know you do not have a whole lot of practice with this)

• Opening files in read or write mode, and closing files
• Reading a line from a file, if necessary splitting it into words and iterating over the words
• Reading a file with a for loop when the number of lines is known, reading it with a sentinel loop when number of lines is unknown
• Writing to files

Practice Problems

1. Write a function called evenize that takes a list of numbers as input and modifies the elements of the list so that all the elements that are even are unchanged, but all odd elements are multiplied by 2.
2. Write a function called extractEvens that takes a list of numbers as input and returns a new list that contains all the even elements of the input list in the same order in which they apppeared in the original list.
3. Determine what would be printed by each of the following pieces of code, and make a table of the values that each variable successively takes while the code is being executed:
   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")

   7.   def printLots(n):
            for i in range(n):
                print("{0:$<5} {1:*>5} {2:!^4}".format(i, i+1, i+2))
      

   8.   def addToList(x,theList):
            for i in range(x):
                theList.append(x)
      
        myList = [1,2,3,4,5]
        addToList(6, myList)
        print(myList)
      

   9.   def doSomething(theList):
            newList = []	    
            for i in range(len(theList)):
                newList.append(theList[i] + 5)
            return newList
      
        myList = [1,2,3,4,5]
        aList = doSometyhing(myList)
        print(myList, aList)
      
      

4. Draw a stack diagram at the point indicated by a comment in the code, and determine what would be printed by the program.

     def main():
         myList = [1,3,5,78,9]
         otherList = doSomethingElse(myList)
         print(otherList)
   
     def doSomethingElse(aList):
         for i in range(len(aList)-1):
             aList[i] = aList[i] + 3
         # draw stack diagram here
         return aList * 2
   
     if __name__ == "__main__":
         main()
   

5. Practice questions on files TBA