Do not display removed sprites, Pygame

Question

I am experiencing an issue with pygame.

I am making a little game and if I die I would like to delete enemies sprites and reload them later when I respawn.

I successfully delete them from their group but they still on the screen when I respawn. But the collide doesn't work anymore. I would like to remove the olds from the screen.

Here's a minimal code for the example :

from pygame import *
import random
import sys
import pygame

WIDTH = 600
HEIGHT = 750
FPS = 60

SPEEDX = 5
SPEEDY = 3

# define colors
BLACK = (0, 0, 0)
RED = (255, 0, 0)
GREEN = (0, 255, 0)

# initialize pygame and create window
pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
clock = pygame.time.Clock()

class Player(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface((40, 40))
        self.image.fill(GREEN)
        self.rect = self.image.get_rect()
        self.rect.centerx = WIDTH / 2
        self.rect.y = HEIGHT

    def update(self):
        self.SPEEDX = 0
        self.SPEEDY = 1
        keystate = pygame.key.get_pressed()

        #Move right
        if keystate[pygame.K_d]:
            self.SPEEDX = SPEEDX
        #Move left
        if keystate[pygame.K_a]:
            self.SPEEDX = - SPEEDX
        #Make the runner run
        if keystate[pygame.K_w]:
            self.SPEEDY = - SPEEDY
        #Close the game
        if keystate[pygame.K_LCTRL] and keystate[pygame.K_z]:
            sys.exit()

        #Make the character moving
        self.rect.x += self.SPEEDX
        self.rect.y -= self.SPEEDY

        #Do not cross screen border
        #Left side
        if self.rect.left < 0:
            self.rect.left = 0
        #Right side
        if self.rect.right > WIDTH:
            self.rect.right = WIDTH
        #Bottom side
        if self.rect.bottom > HEIGHT:
            self.rect.bottom = HEIGHT
        #Top side
        if self.rect.top < 0 :
            self.rect.top = 0

         # if player reaches top 1/4 of screen
        if self.rect.top <= HEIGHT / 4:
            self.rect.centerx = WIDTH / 2
            self.rect.y = HEIGHT

class Enemy(pygame.sprite.Sprite):
        def __init__(self):
            pygame.sprite.Sprite.__init__(self)
            self.image = pygame.Surface((30, 40))
            self.image.fill(RED)
            self.rect = self.image.get_rect()
            self.rect.x = random.randrange(WIDTH - self.rect.width)
            self.rect.y = random.randrange(-100, -40)
            self.speedy = random.randrange(1, 8)
            self.speedx = random.randrange(-3, 3)

        def update(self):
            self.rect.x += self.speedx
            self.rect.y += self.speedy
            if self.rect.top > HEIGHT + 10 or self.rect.left < -25 or self.rect.right > WIDTH + 20:
                self.rect.x = random.randrange(WIDTH - self.rect.width)
                self.rect.y = random.randrange(-100, -40)
                self.speedy = random.randrange(1, 8)

def Death():
    player.rect.centerx = WIDTH / 2
    player.rect.y = HEIGHT
    all_enemies.remove(all_enemies)

player = Player()
enemy = Enemy()

all_sprites = pygame.sprite.Group()
all_enemies = pygame.sprite.Group()
all_sprites.add(player)

for i in range(10):
    enemies = Enemy()
    all_sprites.add(enemies)
    all_enemies.add(enemies)

# Game loop
running = True
while running:
    clock.tick(FPS)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    if sprite.spritecollide(player, all_enemies, False):
        Death()

    # Update
    all_sprites.update()

    # Draw / render
    screen.fill(BLACK)
    all_sprites.draw(screen)
    pygame.display.flip()

pygame.quit()

Answer 1

You're removing the sprites from all_enemies but not from all_sprites. You'll need to manually remove them from all groups they're in, which can be done in two ways:

1. Iterating through the sprite group and call kill() on every sprite.

You cannot modify a group while iterating over it, so you'll have to call sprites() to get a list of all sprites and iterate over it.

for sprite in all_enemies.sprites():
    sprite.kill()

2. Remove them from each list separately.

Just use remove() on all sprite groups.

all_sprites.remove(all_enemies)
all_enemies.empty()  # The same as all_enemies.remove(all_enemies)