21

I'm currently learning python from a book called 'Python for the absolute beginner (third edition)'. There is an exercise in the book which outlines code for a hangman game. I followed along with this code however I keep getting back an error in the middle of the program.

Here is the code that is causing the problem:

if guess in word:
    print("\nYes!", guess, "is in the word!")

    # Create a new variable (so_far) to contain the guess
    new = ""
    i = 0
    for i in range(len(word)):
        if guess == word[i]:
            new += guess
        else:
            new += so_far[i]
        so_far = new

This is also the error it returns:

new += so_far[i]
IndexError: string index out of range

Could someone help me out with what is going wrong and what I can do to fix it?

edit: I initialised the so_far variable like so:

so_far = "-" * len(word)
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2
  • 4
    This is minor and unrelated to your question, but you don't need the i = 0. The for loop automatically sets the loop variable when it starts even if i hasn't been defined yet. Commented Jan 3, 2012 at 13:49
  • @Chad Yeah your right. I can't remember why I stuck that in :S Commented Jan 3, 2012 at 15:01

4 Answers 4

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22

It looks like you indented so_far = new too much. Try this:

if guess in word:
    print("\nYes!", guess, "is in the word!")

    # Create a new variable (so_far) to contain the guess
    new = ""
    i = 0
    for i in range(len(word)):
        if guess == word[i]:
            new += guess
        else:
            new += so_far[i]
    so_far = new # unindented this
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1 Comment

Yes thank you so much! I find it a bit confusing to just have indentation for stuff that I would be used to putting curly brackets around!
6

You are iterating over one string (word), but then using the index into that to look up a character in so_far. There is no guarantee that these two strings have the same length.

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Comments

2

This error would happen when the number of guesses (so_far) is less than the length of the word. Did you miss an initialization for the variable so_far somewhere, that sets it to something like

so_far = " " * len(word)

?

Edit:

try something like

print "%d / %d" % (new, so_far)

before the line that throws the error, so you can see exactly what goes wrong. The only thing I can think of is that so_far is in a different scope, and you're not actually using the instance you think.

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3 Comments

Sorry I should have included this but forgot. I already had that variable initialised in the same way so_far = "-" * len(word)
Edited my response to add a way to debug, and another suggestion as to what may be wrong.
And it looks like @Rob Wouters got it, i missed that. He's right, so_far should be outside the for block :)
1

There were several problems in your code. Here you have a functional version you can analyze (Lets set 'hello' as the target word):

word = 'hello'
so_far = "-" * len(word)       # Create variable so_far to contain the current guess

while word != so_far:          # if still not complete
    print(so_far)
    guess = input('>> ')       # get a char guess

    if guess in word:
        print("\nYes!", guess, "is in the word!")

        new = ""
        for i in range(len(word)):  
            if guess == word[i]:
                new += guess        # fill the position with new value
            else:
                new += so_far[i]    # same value as before
        so_far = new
    else:
        print("try_again")

print('finish')

I tried to write it for py3k with a py2k ide, be careful with errors.

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1 Comment

Yeah I only took out a small segment of code to get to the point. Thanks for pointing it out though.

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