Project 3 — Strings

Complete the following problems.

Setup

To begin, use PyCharm to create a project called project3. You should do all your work there.

Next, download project3.zip. This is a zip file, so you will need to extract its contents. You should put the files inside of your project3 folder.

Most of the problems will have you use the string_functions.py file.

For all functions, be sure to write documentation and doctests. Be sure to write tests that cover a variety of situations. We will be automatically grading your code with a complete set of tests, so the better you test your code the better your score!

Non-Alpha

Write a function in string_functions.py called has_non_alpha(s) which returns true if the string contains non-alphabetic characters. For example:

>>>  has_non_alpha('abcd')
False
>>> has_non_alpha('as90')
True

Censor

Write a function in string_functions.py called censor(text). This takes one parameter:

• text: a string

If text contains ‘SUPER SECRET’, then the whole string becomes asterisks, but if not, all UPPERCASE characters become asterisks. For example:

>>> censor('This is a SUPER SECRET message')
'******************************'
>>> censor('That is SUPER crazy')
'*hat is ***** crazy'

Reverse

Write a function in string_functions.py called reverse_case(s). This function takes one parameter:

• s: a string

It returns a new string, where all lowercase characters in s become UPPERCASE and all UPPERCASE characters become lowercase, with all other characters staying the same. For example:

>>> reverse_case('abC!')
'ABc!'

Remove prompt

Write a function in string_functions.py called remove_prompt(s). This function takes one parameter:

• s: a string

It returns a new string, which contains all characters after the first occurence of :. If there is no prompt, it returns the text unmodified. For example:

>>> remove_prompt('anna: stuff')
' stuff'
>>> remove_prompt('hello')
'hello'
>>> remove_prompt('name:')
''

Important

Write a function in string_functions.py called is_important(s). This function takes one parameter:

• s: a string

If the string starts with ‘important’, return the string with ‘important’ replaced with ‘THIS IS IMPORTANT’, otherwise do nothing (note: the string may contain ‘important’ in other parts, and these should be ignored. For example:

>>> is_important('important: meeting tomorrow')
'THIS IS IMPORTANT: meeting tomorrow'
>>> is_important('there is an important meeting tomorrow')
'there is an important meeting tomorrow'

Crazy

Write a function in string_functions.py called crazy(s). This function takes one parameter:

• s: a string

It returns a new string where every alphabetic character is doubled, every digit is tripled, every space is replaced with _, and everything else is left unchanged. For example:

>>> crazy("It's 90 degrees outside!")
"IItt'ss_999000_ddeeggrreeeess_oouuttssiiddee!"

Vowel count

Write a function in string_functions.py called vowel_count(s). This function takes one parameter:

• s: a string

The function returns a count of the number of vowels in the string. For example:

>>> vowel_count('What a beautiful day!')
8

Many times

Write a function called many_times(s, maximum). This function takes two parameters:

• s: a string
• maximum: an integer

The function returns a new string that has s repeated until the maximum length of maximum characters is exceeded. For example:

>>> many_times('hurray',10)
'hurrayhurray'
>>> many_times('yes',20)
'yesyesyesyesyesyesyes'

Remember that you can use ”+” to concatenate strings, so 'hello'+'hello' is 'hellohello'.

Collect

Write a function in string_functions.py called collect(s, stop). This function takes two parameters:

• s: a string
• stop: another string

The function returns all characters in s before the first time the string in stop occurs. If stop is the empty string or if stop does not occur, all characters in s are returned.

For example:

>>> collect('what a lovely day it is', 'lovely')
'what a '
>>> collect('tomorrow is the first day of the rest of your life','rest')
'tomorrow is the first day of the '

Replace

Write a function in string_functions.py called replace(s, phrase1, phrase2). This function takes three parameters:

• s: a string
• phrase1: a string to replace
• phrase2: a string to put in place of phrase2

The function returns a new string that removes the first occurrence of phrase in s and replaces it with phrase2.

For example:

>>> replace('tomorrow is the first day of the rest of your life','rest','best')
'tomorrow is the first day of the best of your life'
>>> replace('tomorrow is the first day of the rest of your life', 'of the rest of your life', 'of realizing your greatest potential')
'tomorrow is the first day of realizing your greatest potential'

Wordle

If you have not played Wordle before, you should play it enough so that you understand how it works. In Chrome you can use File->New Incognito Window to replay the current game so you can see how it works. Note that you are always guessing a five letter word, and the game tells you if a letter is correct and in the right spot (green), correct but in the wrong spot (yellow) or incorrect (gray).

For this problem, you will be working in wordle_helper.py. You will see three functions there that you need to test and write. We have provided the documentation for you, but be sure to create doctests!

Check for a valid guess

The first function is valid_guess(word). This function takes one parameter:

• word: a string

The function checks whether a guess is valid — the length of the word must be exactly 5 characters, and all characters must be alphabetic. It returns True only if the word is a valid guess, False otherwise.

Filter letters

The second function is filter_letters(word, alphabet). This function helps us to keep track of which letters the player has not guessed yet. It takes two parameters:

• word: a word the user guesses
• alphabet: a list of letters the user has not guessed yet

The function returns a new string, which contains all the letters in alphabet that are NOT in `word.

Score the guess

The third function is score_guess(guess, truth, wrong, close, correct). This function scores a player’s guess. It takes five parameters:

• guess: the word the player guesses
• truth: the word being guessed
• wrong: the character used to indicate a wrong guess
• close: the character used to indicate a close guess
• correct: the character used to indicate a correct guess

The function should return a new string that is a sequence of wrong, close, and correct characters that indicate the score for the player’s guess. For example:

>>> score_guess("abcde", "abcde", '-', '*', '#')
'#####'

>>> score_guess("abcde", "annex", '-', '*', '#')
'#---*'

Here, we are using - for wrong, * for close and # for correct. They really could be any characters. In the first example, the user guesses the word correctly, so the returned string is #####. In the second example, the user has two letters, one close and one correct. The a is correct, but the e is in the wrong position. All the other letters are wrong.

You know you can loop over the characters in a string. Did you know you can loop over two strings simultaneously? If strings first and second have the same length, then:

for i in range(len(first)):
  character_in_first = first[i]
  character_in_second = second[i]

Playing wordle

Once you have these functions tested, you can use:

python wordle.py

and play the game. Our version uses a red square emoji for the wrong letters, a yellow square for the close letters (wrong position), and a green square for correct letters. Enjoy!

Submit

You need to submit:

• string_functions.py
• wordle_helper.py

Points

This project is worth 40 points.

The auto grader on GradeScope will grade whether your solution works. The TAs will grade your docstrings and decomposition as follows:

• Docstrings
  • 2 points: You have docstrings that clearly explain waht the function does, what each parameter does and the return value
  • 1 points: Your docstrings need some improvement
  • 0 points: No docstrings or only a few docstrings
• Doctests
  • 5 points: Your doctests cover a good range of test cases
  • 3 points: You have doctests but need to test more cases
  • 0 points: You do not have doctests

The TAs may award points between 0 and 3 and between 3 and 5 if you are in betweeen these scores.