Hangman - Invent Your Own Computer Games with Python - page 134

Checking if the Letter is in the Secret Word
118. if guess in secretWord:
119. correctLetters = correctLetters + guess
Now let's see if the single letter in the guess string exists in secretWord . If it does
exist, then we should concatenate the letter in guess to the correctLetters string.
Next we can check if we have guessed all of the letters and won.
Checking if the Player has Won
121. # Check if the player has won
122. foundAllLetters = True
123. for i in range(len(secretWord)):
124. if secretWord[i] not in correctLetters:
125. foundAllLetters = False
126. break
How do we know if the player has guessed every single letter in the secret word? Well,
correctLetters has each letter that the player correctly guessed and secretWord is
the secret word itself. We can't just check if correctLetters == secretWord
because consider this situation: if secretWord was the string 'otter' and
correctLetters was the string 'orte' , then correctLetters ==
secretWord would be False even though the player has guessed each letter in the
secret word.
The player simply guessed the letters out of order and they still win, but our program
would incorrectly think the player hasn't won yet. Even if they did guess the letters in order,
correctLetters would be the string 'oter' because the player can't guess the letter t
more than once. The expression 'otter' == 'oter' would evaluate to False even
though the player won.
The only way we can be sure the player won is to go through each letter in
secretWord and see if it exists in correctLetters . If, and only if, every single letter
in secretWord exists in correctLetters will the player have won.
Note that this is different than checking if every letter in correctLetters is in
secretWord . If correctLetters was the string 'ot' and secretWord was
'otter' , it would be true that every letter in 'ot' is in 'otter' , but that doesn't mean
the player has guessed the secret word and won.
So how can we do this? We can loop through each letter in secretWord and if we find
a letter that does not exist in correctLetters , we know that the player has not guessed
all the letters. This is why we create a new variable named foundAllLetters and set it