if 语句检查 sprite.Group = 0

Question

I trying to create game using pygame,then using myTarget=pygame.sprite.Group() My problem is how to create if statement that tell if myTarget=0, I already using

if myTarget=="0"

and

if myTarget == [0]

But none of that code triggered, I also already checked that inside that group no more sprites (using print(myTarget) that says <Group(0 sprites)> Sorry for my English

Answer 1

Unfortunately the SpriteGroup object is not able to be directly indexed.

You can use the SpriteGroup.sprites() member function, which returns a python list of all the elements and then just tested item 0 in that list:

import pygame

class SimpleSprite( pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface( ( 64, 64 ), pygame.SRCALPHA )
        self.image.fill( ( 255, 255, 12 ) )
        self.rect = self.image.get_rect()


pygame.init()

sprite_group = pygame.sprite.Group()  # empty group

# Make and add 3 sprites to the group
sprite_a = SimpleSprite()
sprite_b = SimpleSprite()
sprite_c = SimpleSprite()
sprite_group.add( sprite_a )
sprite_group.add( sprite_b )
sprite_group.add( sprite_c )

print( "Group has %d sprites" % ( len( sprite_group ) ) )

if ( sprite_a == sprite_group.sprites()[0] ):                 # <<-- HERE
    print( "Sprite A is the 0th item in the group" )
else:
    print( "Sprite A is NOT the 0th item" )

Which gives me the output:

...
Group has 3 sprites
Sprite A is the 0th item in the group

Also you can use the len() function on a Sprite Group to test if it is empty.