Python 2.6: "Couldn't open image" error

Question

I'm trying to make the base for a map that I'm going to be using for a game, but I can't load the image onto the screen. I've tried sending in an absolute filepath to the image with likesame letter case, I've tried changing the name of the image, I've tried loading different images that worked in other programs I made, and I've tried putting the image in the same directory as the script itself. Nothing has worked yet. I looked at a few threads of people who were having the same problem, such as Why are my pygame images not loading? and I can't find the answer to my problem. The image will not load. Here's the code:

import sys, pygame
from pygame.locals import *

pygame.init()
size = (600, 400)
screen = pygame.display.set_mode(size)
pygame.display.set_caption("Practice Map")
walls = pygame.image.load("C:\Users\dylan\Desktop\Practice Game\brick.jpg")

x = 0
y = 0

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        if event.type == KEYDOWN and event.key == K_ESCAPE:
            sys.exit()
        if event.type == KEYDOWN and event.key == K_UP:
            y -= 20
        if event.type == KEYDOWN and event.key == K_DOWN:
            y += 20
        if event.type == KEYDOWN and event.key == K_LEFT:
            x -= 20
        if event.type == KEYDOWN and event.key == K_RIGHT:
            x += 20
        screen.fill((0,0,0))
        screen.blit(walls,(x, 330))
        # more bricks to go here later
        pygame.display.flip()

#end

and the error:

Traceback (most recent call last):
  File "C:\Users\dylan\Desktop\Practice Game\move.py", line 8, in <module>
    walls = pygame.image.load("C:\Users\dylan\Desktop\Practice Game\brick.jpg")
error: Couldn't open C:\Users\dylan\Desktop\Practice Gamerick.jpg

I'm using Python 2.6 with PyGame 1.9 for Python version 2.6 with IDLE as my editor.

abarnert · Accepted Answer · 2013-02-05T23:52:43.303

The problem here is that you're using \ as a pathname separator, but \ is also used as an escape character in Python strings. In particular, \b means "backspace" (or '\x08'). You get away with the other backslashes because of not-quite-documented-but-reliable behavior that unknown escape sequences like \X are treated as a backslash followed by an X.

There are three solutions:

Use a raw string, which means Python string escapes are ignored: r"C:\Users\dylan\Desktop\Practice Game\brick.jpg".
Escape your backslashes: "C:\\Users\\dylan\\Desktop\\Practice Game\\brick.jpg".
Use forward slashes instead: "C:/Users/dylan/Desktop/Practice Game/brick.jpg".

If you've memorized the list of Python escape sequences, and are willing to rely on functionality that may change but probably won't, you can get away with only escaping the \b here, but it should be clear why the other three are better ideas in the long run.

While Windows pathnames do natively use backslash separators, all built-in and standard-library Python functions, and most functions in third-party libraries, are perfectly happy to let you use forward slashes instead. (This works because Windows doesn't allow forward slashes in paths at all.)

To understand how and why this works, you might want to try printing out the strings:

>>> print "C:\Users\dylan\Desktop\Practice Game\brick.jpg"
C:\Users\dylan\Desktop\Practice Gamrick.jpg
>>> print r"C:\Users\dylan\Desktop\Practice Game\brick.jpg"
C:\Users\dylan\Desktop\Practice Game\brick.jpg
>>> print "C:\\Users\\dylan\\Desktop\\Practice Game\\brick.jpg"
C:\Users\dylan\Desktop\Practice Game\brick.jpg
>>> print "C:/Users/dylan/Desktop/Practice Game/brick.jpg"
C:/Users/dylan/Desktop/Practice Game/brick.jpg

elssar · Answer 2 · 2013-02-05T23:51:57.217

4

walls = pygame.image.load("C:\Users\dylan\Desktop\Practice Game\brick.jpg")

You need to escape the last \

walls = pygame.image.load("C:\Users\dylan\Desktop\Practice Game\\brick.jpg")

Edit: Explanation

You need to escape on the last \ because there is a b right after the \, and \b is an escape sequence for backspace. This deletes the character before the sequence. This is why you need to escape the last backslash.

edited Feb 05 '13 at 23:51

answered Feb 05 '13 at 23:40

elssar

5,651
7
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Really? All the examples I've seen didn't and they worked. I'll try it now. – Dylan LaCoursiere Feb 05 '13 at 23:42
You need to explain _why_ he has to escape the last \ but not any of the earlier ones (at least one of which also comes before a lowercase letter). Or, better, just tell him to escape _all_ of the \ characters. Or, even better, to use a raw string or use `/` characters instead. – abarnert Feb 05 '13 at 23:44
It worked, but I didn't have to do that with any of my other programs and they worked fine. Why would one program be picky and another not? I'm not doing anything different. – Dylan LaCoursiere Feb 05 '13 at 23:46
1

`\b` is a an escape sequence. Notice how your error reads `Gamerick.jpg` and not `Game\brick.jpg`. Since windows paths use backspaces as a path separator, consider using raw strings instead to turn off escape sequence interpretation: `r"Game\brick.jpg"` – Francis Avila Feb 05 '13 at 23:48
I'll be damned. Not one book, video, or anything of the sort ever explained that. Leave it to Microsoft to make things harder for its users. – Dylan LaCoursiere Feb 05 '13 at 23:55
1

@DylanLaCoursiere: Just wait until you try to use a regular expression to match a Windows patch with Python escape sequences in it. :) And yes, this is an annoyance. But you can't blame Microsoft; it's really mostly IBM's fault. See http://blogs.msdn.com/b/larryosterman/archive/2005/06/24/432386.aspx – abarnert Feb 06 '13 at 01:27

score 2 · Answer 3 · answered Feb 05 '13 at 23:45

2

Note that Windows paths use the \ character as separators. Those also mean "escape" in a Python string.

Try using a raw string instead:

walls = pygame.image.load(r"C:\Users\dylan\Desktop\Practice Game\brick.jpg")

(Note the r" in front of the string.)

answered Feb 05 '13 at 23:45

Thane Brimhall

9,256
7
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Python 2.6: "Couldn't open image" error

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