list won't change values for pygame rectangles

Question

I have been trying to recreate snake in pygame for fun but the list won't update for the rectangle positions, anyone know what I'm doing wrong with this code???

I passed in a list within a list (snake_body) to a function with this code however the list within a list doesn't change its integer values

if event.key == pygame.K_UP or pygame.K_w:
    snake_body[0][1] -= 50

if event.key == pygame.K_DOWN or pygame.K_s:
    snake_body[0][1] += 50

if event.key == pygame.K_RIGHT or pygame.K_d:
    snake_body[0][0] += 50

if event.key == pygame.K_LEFT or pygame.K_a:
    snake_body[0][0] -= 50

    print(snake_body)

>>> [[370, 50, 30, 30]]

but the up output should be >>> [[320, 50, 30, 30]]

anything would be helpful as I have been stuck on this for a day and it is no longer fun.

There's not enough here for us to tell what is wrong. What happens when you run your code.. do the if statements get triggered? Is snake_body being printed? Do you get any errors? What is [[int, int, int, int]]? Why do you have a list of types? — JeffUK, Jan 29 '22 at 20:45
might wanna take a look at how to ask a good question: [How to ask](https://stackoverflow.com/help/how-to-ask) and more specifically [create a minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) — AntiMatterDynamite, Jan 29 '22 at 20:51
Maybe it can be useful to give us a real sample of the list and what you expect as the code's output. — Happy Ahmad, Jan 29 '22 at 20:58

score 2 · Answer 1 · answered Jan 29 '22 at 20:58

See How to test multiple variables for equality against a single value?. A condition like

if event.key == pygame.K_UP or pygame.K_w:

does not do what you expect. It always evaluates to True. The correct syntax is:

if event.key == pygame.K_UP or event.key == pygame.K_w:

list won't change values for pygame rectangles

1 Answers1