(IndexError: list index out of range) My for loop is giving me an error?

Question

Here is my code:

import game, pygame, sys
from gameobjects import *
from imageloader import *




def main():
    screen = pygame.display.set_mode( (800, 600) )
    background = Background("images/Nebula1.bmp", screen.get_width(), screen.get_height())
    letter1 = pygame.image.load("1.bmp")
    letter2 = pygame.image.load("2.bmp")
    letter3 = pygame.image.load("3.bmp")
    letter4 = pygame.image.load("4.bmp")
    letter5 = pygame.image.load("5.bmp")
    letter6 = pygame.image.load("6.bmp")
    letter7 = pygame.image.load("7.bmp")
    letter8 = pygame.image.load("8.bmp")
    letter9 = pygame.image.load("9.bmp")
    letter10 = pygame.image.load("10.bmp")
    Letters = [letter1, letter2, letter3, letter4, letter5, letter6, letter7, letter8, letter9, letter10]
    letter = 0

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                sys.exit()

        screen.blit(background.image, (0,0))

        for i in Letters:
            screen.blit( Letters[letter], (330 + 14 * letter, 190) )
            letter += 1


        pygame.display.flip()
All the items in the Letters list are pygame.Surfaces retrieved through using pygame.image.load(). Every time I run this code, I get an error that looks like this:

    Traceback (most recent call last):
      File "main.py", line 75, in <module>
        main()
      File "main.py", line 32, in main
        screen.blit( Letters[letter], ((330 + 14 * letter, 190)) )
    IndexError: list index out of range

Why is this happening? It seems perfectly valid to me. What am I doing wrong? What I want to do is paste each letter on the screen 14 pixels over from the last one, because each one is 14 pixels wide. Any help? (I am new to python so if I made a dumb mistake, forgive me.)

agconti · Accepted Answer · 2014-08-21 03:52:42Z

2

You have to set letter = 0 for each iteration. Because its outside of the while loop, letter is only set to 0 on initialization. Afterwards it throws an IndexError as on the second iteration of the for i in letters, as letter is now equal to the length of the letters because of the last iteration!

Use enumerate() to safety and easily increment:

for i,val in enumerate(Letters):
        screen.blit( Letters[i], (330 + 14 * letter, 190) )

or alternatively, include letter = 0 inside the while loop:

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()

    screen.blit(background.image, (0,0))

    letter = 0
    for i in Letters:
        screen.blit( Letters[i], (330 + 14 * letter, 190) )
        letter += 1

edited Aug 21, 2014 at 3:52

answered Aug 21, 2014 at 3:04

agconti

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10 Comments

number1son10 Over a year ago

It ran, but I ran into another problem. When I run it, the letters don't really print to the screen, they just really quickly slide across it.... Do you know why that might be happening?

agconti Over a year ago

I'm not quite sure what you mean. Since these are two different questions, you should ask another one about the new issue. If my answer solved you first problem, can you please accept my answer?

number1son10 Over a year ago

What I meant was that the for loop doesn't do what it was supposed to do, that was what I wanted an answer to. That was the question, cuz I still have an error, just not the same error.

Barmar Over a year ago

Where is the bad for loop in the question? Please don't edit away the error, how is anyone supposed to understand what this answer is fixing?

number1son10 Over a year ago

Oh oops sorry I was adding the rest of the code, I'll change the error back. It was in the copy paste.

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