Final Exam Review

Survey Results

• 8/12 students submitted the survey
• 4 wanted conceptual-only, 4 wanted conceptual & programming – conceptual-only final exam
• Format for review:
  • Lecture-style: 44%
  • Open class: 29%
  • Question & Answer: 27%
• Preferred Focus of Review:
  • Concepts: 75%
  • Programming: 25%
• Ranking of topics:
  • Classes: 27%
  • Modules: 19%
  • Exception Handling: 17%
  • Dictionaries and Sets: 17%
  • Functions: 14%
  • Midterm Material: 7%

Classes

Requests:

• would like to see some detailed examples on classes, as well as more information on when they are useful/when they aren't.
• review of data aggregation for secure set methods (copies)?
• Data Aggregation.  If we could have another example like the eye and hair color program, only much shorter and more simple, that would be wonderful
• data aggregation
• What is the property function? How to make a field private? How do methods access and use fields that are private? How does the end user access and use private fields?
• No specific questions, just need more conceptual understanding and practice.
• These lectures were just overall where I become very lost in the course.  I need a lot of help with these topics in general

Examples and Discussion Topics:

1. You have been asked to replace CourseWeb with something that is nicer to use. Design the data structures to represent the following:
   • a course
   • assignments
   • tests
   • users
2. Find and fix the data aggregation security problems in the code below: class Values:
       def __init__(self, vals):
           self.__values = vals
           
       def get_all(self):
           return self.__values
           
       def set_all(self, values):
           self.__values = values
           
   
3. Write a copy method for the Values class above.
4. Write a PositiveValues class. This class stores a collection of positive numbers and must support the operations shown below. Be sure to address all data aggregation security concerns.
   • a constructor that takes a collection of values and saves them into the object (non-positive numbers are converted to positive; all other non-positive values are ignored)
   • a get_all method that returns the collection of positive values stored in the object
   • a set_all method that takes a collection of values and saves them into the object (non-positive numbers are converted to positive; all other non-positive values are ignored)
   • a get method that takes a position in the object's collection and returns the value at that position
   • an append method that takes a value and:
     1. if it is a positive number, appends it to the object's collection
     2. if it is a negative number, converts it to positive and appends it to the object's collection
     3. if it is any other value, it raises a ValueError exception
   • the __len__ special method

Modules

Requests:

• These lectures were just overall where I become very lost in the course.  I need a lot of help with these topics in general

Examples and Discussion Topics:

1. Modules are source code files primarily with function and class definitions and are intended to be used in other programs (by other programmers)
2. sys.path
3. An aside: sys module vs. os module

Exception Handling

Requests:

• I have a hard time with the exception questions in which an exception is raised but not handled by the same part of the program.  Those get very confusing and I spend too much time on those questions.
• When do I have to handle exceptions? Do I always have to? How exactly do I know when an exception should be handled/shouldn't?
• What does it mean to manually raise an exception, and when/how should I do it? (still pretty confused on this, especially).
• Exception propagation

Examples and Discussion Topics:

1. What is the output of the following code snippet? print('a')
   try:
       print('b')
       raise ValueError
       print('c')
   except TypeError:
       print('d')
   except ValueError:
       print('e')
   print('f')
   
2. What is the output of the following code snippet? def functionA():
       print('a')
       raise ValueError
       print('b')
   def functionB():
       print('c')
       try:
           functionA()
           print('d')
       except TypeError:
           print('e')
       print('f')
   print('g')
   try:
       functionB()
       print('h')
   except ValueError:
       print('i')
   

Dictionaries and Sets

Requests:

• review of difference between dictionaries and sets and examples of an application of each?
• No specific questions, just need more conceptual understanding and practice.

Examples and Discussion Topics:

1. For each of the following cases, which data structure would you use (list, set, or dict)?
   • Hold a collection of items that are hashable -- you don't want duplicates
   • Hold a collection of items that are not hashable -- you don't want duplicates
   • You have a collection of items and want to be able to look up values with a specific label (i.e. a specific label is associated with each value)
   • You have a collection of items and you want to remove duplicates
   • You have a collection of items and all you're interested in (ever) is whether values are in the collection or not
   • You have a collection of items and each value has a specific label associated with it
   • You want to hold a collection of items and do not care about order

Functions

No questions submitted.

Midterm Material

No questions submitted.