Pygame key getting pressed

Question

What is the idiomatic way of saying to pygame to run something as long as a key is being pressed? With pygame.key.get_pressed()[pygame.K_p]==True or pygame.mouse.get_pressed()==(1,0,0) it seems to react only as the key or the button get strocken. Should one use a while loop for example?

I run the code below and i get print in the shell only upon strocking the key/button:

def main():
done = True
while done:
    for i in pygame.event.get():
        if pygame.key.get_pressed()[pygame.K_a] == 1:
            print "Key a is being pressed..."
        elif i.type == KEYDOWN and i.key == pygame.K_q:
            done = 0
    pygame.display.update()
pygame.quit()
main()

Answer 1

Event KEYDOWN means "key changed state from UP to DOWN" - it doesn't means "key is held pressed all time"

When you start pressing key - it generate event KEYDOWN and pygame.event.get() returns not empty list - and for loop can execute if pygame.event.get()

When you hold key pressed - it doesn't generate event KEYDOWN - and pygame.event.get() returns empty list - and for loop doesn't execute if pygame.event.get()

Your code should looks like

running = True
while running:
    # check events 
    for event in pygame.event.get():
        if event.type == KEYDOWN:
            if event.key == pygame.K_q:
               running = False

    # do it outside of `for event` loop
    # it is executed many times 
    if pygame.key.get_pressed()[pygame.K_a]: 
        print "Key is hold pressed..."

    pygame.display.update()

or - when you need to execute something only once

key_A_pressed = False

running = True
while running:
    # check events 
    for event in pygame.event.get():
        if event.type == KEYDOWN:
            if event.key == pygame.K_q:
               running = False

            elif event.key == pygame.K_a:
               key_A_pressed = True

               # it is executed only once
               print "Key A - start pressing"

        if event.type == KEYUP:
            if event.key == pygame.K_a:
               key_A_pressed = False

               # it is executed only once
               print "Key A - stop pressing"

    # do it only once - outside of `for event` loop
    # it is executed many times 
    #if pygame.key.get_pressed()[pygame.K_a]: 
    # or
    if key_A_pressed:
        print "Key A is held pressed..."

    pygame.display.update()