pygame keeps keys pressed even after a new start of the game

Question

I have a strange behavior with when using pygame.

[...]
pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
[...]
while running:
    [...]
    dt = (new_time - start_time).total_seconds()
    keys = pygame.key.get_pressed()
    if keys[pygame.K_DOWN]:
        bot.brake(dt)
    elif keys[pygame.K_UP]:
        bot.accelerate(dt)

Sometimes, even if I am not pushing any key, it instantaneously starts to accelerate the bot. When I debug, I found that the key is pressed for pygames, even if I don't touch the keyboard. That happens even on a fresh start of the game.

Can you help me find the cause of this problem?

Answer 1

You may be able to use variables to manupulate and figure out what keys you're pressing. Though I like detecting Keypress in another function.

[...]
var MD,MU=False,False,False
[...]

def check():
        for event in pygame.event.get():
            if event.type==pygame.QUIT:
                sys.exit()
            if event.type==pygame.KEYDOWN:
                if event.key==pygame.K_DOWN:
                    MD=True
                if event.key==pygame.K_UP:
                    MU=True
            elif event.type==pygame.KEYUP:
                elif event.key==pygame.K_UP:
                    MU=False
                elif event.key==pygame.K_DOWN:
                    MD=False

Now you have to create a function to control you player.

def controlPlayer():
      if MU:
           #do what you want when up  button is pressed
      if MD:
           #do what you want when down button is pressed

Then you implement both of these functions into the "While running" script

while running:
     check()
     controlPlayer()