Week 4 - Problem Set 4

[tiagomestreteixeira]

Problem Set 4

In this problem set, you'll implement two versions of a wordgame!

Let's begin by describing the 6.00 wordgame: This game is a lot like Scrabble or Words With Friends, if you've played those. Letters are dealt to players, who then construct one or more words out of their letters. Each valid word receives a score, based on the length of the word and the letters in that word.

The rules of the game are as follows:

Dealing

• A player is dealt a hand of n letters chosen at random (assume n=7 for now).
• The player arranges the hand into as many words as they want out of the letters, using each letter at most once.
• Some letters may remain unused (these won't be scored).

Scoring

• The score for the hand is the sum of the scores for each word formed.
• The score for a word is the sum of the points for letters in the word, multiplied by the length of the word, plus 50 points if all n letters are used on the first word created.
• Letters are scored as in Scrabble; A is worth 1, B is worth 3, C is worth 3, D is worth 2, E is worth 1, and so on. We have defined the dictionary SCRABBLE_LETTER_VALUES that maps each lowercase letter to its Scrabble letter value.
• For example, 'weed' would be worth 32 points ((4+1+1+2) for the four letters, then multiply by len('weed') to get (4+1+1+2)*4 = 32). Be sure to check that the hand actually has 1 'w', 2 'e's, and 1 'd' before scoring the word!
• As another example, if n=7 and you make the word 'waybill' on the first try, it would be worth 155 points (the base score for 'waybill' is (4+1+4+3+1+1+1)*7=105, plus an additional 50 point bonus for using all n letters).

Problems

• Problem 1
• Problem 2
• Problem 3
• Problem 4
• Problem 5
• Problem 6
• Problem 7

Getting Started

1. Download and save Problem Set 4, a zip file of all the skeleton code you'll be filling in. Extract the files from the zip folder and make sure to save all the files - ps4a.py, ps4b.py, test_ps4a.py and words.txt - in the same folder. We recommend creating a folder in your Documents folder called 6001x, and inside the6001x folder, creating a separate folder for each problem set. If you don't follow this instruction, you may end up with issues because the files for this problem set depend on one another.

2. Run the file ps4a.py, without making any modifications to it, in order to ensure that everything is set up correctly (this means, open the file in IDLE, and use the Run command to load the file into the interpreter). The code we have given you loads a list of valid words from a file and then calls the playGame function. You will implement the functions it needs in order to work. If everything is okay, after a small delay, you should see the following printed out:

Loading word list from file...
      83667 words loaded.
playGame not yet implemented.

If you see an IOError instead (e.g., "No such file or directory"), you should change the value of the WORDLIST_FILENAME constant (defined near the top of the file) to the complete pathname for the file words.txt (This will vary based on where you saved the files).

For example, if you saved all the files including this words.txt in the directory "C:/Users/Ana/6001x/PS4" change the line:

WORDLIST_FILENAME = "words.txt" to something like
WORDLIST_FILENAME = "C:/Users/Ana/6001x/PS4/words.txt"
Windows users, if you are copying the file path from Windows Explorer, you will have to change the backslashes to forward slashes.

The file ps4a.py has a number of already implemented functions you can use while writing up your solution. You can ignore the code between the following comments, though you should read and understand how to use each helper function by reading the docstrings:

# -----------------------------------
# Helper code
# You don't need to understand this helper code,
# but you will have to know how to use the functions
# (so be sure to read the docstrings!)
    .
    .
    .
# (end of helper code)
# -----------------------------------   

This problem set is structured so that you will write a number of modular functions and then glue them together to form the complete word playing game. Instead of waiting until the entire game is ready, you should test each function you write, individually, before moving on. This approach is known as unit testing, and it will help you debug your code.

We have provided several test functions to get you started. After you've written each new function, unit test by running the file test_ps4a.py to check your work.

If your code passes the unit tests you will see a SUCCESS message; otherwise you will see a FAILURE message. These tests aren't exhaustive. You will want to test your code in other ways too.

Try running test_ps4a.py now (before you modify the ps4a.py skeleton). You should see that all the tests fail, because nothing has been implemented yet.

These are the provided test functions:

test_getWordScore()
Test the getWordScore() implementation.

test_updateHand()
Test the updateHand() implementation.

test_isValidWord()
Test the isValidWord() implementation.