Top-down shooter in Pygame-- deleting bullets leads to problems - object

Question

I am trying to program a top-down shooter game in Python and I'm a problems with controlling and removing bullets. To summarize, I have a class for the ship the player controls and a class for the bullets the ship produces when the player fires. The bullets propel upward on the screen and once they exit the playing view, they are removed. The problem is that when bullets get removed, something goes wrong. I'm not sure what it is (I think it's the for loop that handles moving and deleting all the bullets) but I get this weird misalignment with the left-side bullets like when the game has to remove a bullet, it skips (just for a single frame) over moving the left bullet just below the top of the screen while the right bullet remains unaffected. The
Here's an image for reference.
Here is the bullet class:
class Bullet():
def __init__(self, gun_pos):
self.image = pygame.image.load('Images/Bullet.png').convert()
self.rect = self.image.get_rect(midbottom = gun_pos)
play_surface.blit(self.image, self.rect)
def move(self):
self.rect.move_ip(0, -8)
def draw(self):
play_surface.blit(self.image, self.rect)
This part handles firing. If the player presses the 'fire' key and if the player isn't reloading, then the game produces two bullets at the top right and left corners of the player ship.
if not player.reloading and firing:
bullet = Bullet(player.rect.topleft)
bullets.append(bullet)
bullet = Bullet(player.rect.topright)
bullets.append(bullet)
player.reloading = 4
Here is the portion of the main loop that handles moving bullets and removing them from the game when they exit the top of the main surface.
while running:
for bullet in bullets:
bullet.move()
if bullet.rect.bottom < 0:
bullets.remove(bullet)
continue
If I split the for-loop into two for-loops with one loop handling moving the bullets and another checking if they need to be removed, there's no misalignment but I'm curious why bunching the loops together causes the problem.
Here is the part of the code that handles drawing the graphics, including the player and the enemies:
pygame.draw.rect(play_surface, (0, 0, 0), SCREEN_RECT)
player.draw()
for enemy in enemies:
enemy.draw()
for bullet in bullets:
bullet.draw()
pygame.display.flip()
I've implemented an enemy and I'm having a similar problem when bullets hit the enemy. If two bullets hit at once, then the bullet on the right will not be removed until the next frame.

Answer 1

you should use the pygame Sprites & Groups.
delete your move and draw method.
make a update method in your bullet class.
def update(self):
self.rect.move_ip(0, -8)
if self.rect.bottom < 0: self.kill()
make a spritegroup for your bullets, and add your bullets to it.
the bulletGroup.update() method call the update() method for each bullet.
bulletGroup = pygame.sprite.Group()
bulletGroup.add(bullets)
while True:
# do your stuff
bulletGroup.update()
# do your other stuff
pygame.display.flip()