How to append the same variable multiple times that defines a class - python-3.x

Question

Here is the class NPC:
class NPC:
def __init__(self):
self.x = randint(0,800)
self.y = randint(0,60)
self.velocity_x = 5
self.drop_y = 60
self.img = "my image path here"
npc = NPC()
num_npc = 5
list = []
for i in range(num_npc):
list.append(npc)
In the game loop only one image is shown and is stationary.
I'm working on trying to write old code to be object oriented and can't figure out the best way to render the npcs
Below is the old code I was using and it worked as expected
npc_img = []
npc_x = []
npc_y = []
npc_vel_x = []
npc_vel_y = []
num_of_npc = 5
for i in range(num_of_npc):
npc_img.append("my img path")
npc_x.append(random.randint(0, 800))
npc_y.append(random.randint(0, 60))
npc_vel_x.append(4)
npc_vel_y.append(40)

Answer 1

Your code is pretty much correct already. However the way you are creating instances of NPC objects is not quite correct. I guess you meant to add 5 NPCs to the list, not 5 references to the same NPC object. That is what your question title says though!
npc = NPC()
...
for i in range(num_npc):
list.append(npc) # <<-- HERE, same object, 5 times
The code should call the NPC constructor in the loop, rather than outside it.
for i in range( num_npc ):
new_npc = NPC()
list.append( new_npc )
While you're rewriting code, it might be worth keeping the co-ordinates and image dimensions in a Pygame Rect, since this allows for easy collision detection and other nice things.
Something like:
class NPC:
def __init__(self):
self.image = pygame.image.load( "image path here" ).convert_alpha()
self.rect = self.image.get_rect()
self.rect.x = randint(0,800)
self.rect.y = randint(0,60)
self.velocity_x = 5
self.drop_y = 60
def draw( self, screen ):
screen.blit( self.image, self.rect )
def hitBy( self, arrow_rect ):
hit = self.rect.colliderect( arrow_rect )
return hit

Answer 2

If I understood correctly, something like this should work:
class NPC:
def __init__(self):
self.x = randint(0,800)
self.y = randint(0,60)
self.velocity_x = 5
self.drop_y = 60
self.image_list = []
self_image_load_dict = {}
def add_image(self, image_path):
self.image_list.append(image_path)
def load_images(self):
self.image_load_dict[]
for i in len(self.get_image_list()):
self.image_load_dict[i] = pygame.image.load(self.get_image_list()[i])
def get_image_list(self):
return self.image_list
def get_image_load_dict(self):
return self.image_load_dict
I used fstring so it would be easier to load images and keep track of the image number:
npc = NPC()
for i in range(NUMBER_OF_NPC):
npc.add_image(f"image_path_{i}")
Now you have image_paths in the object's list, I assume you want to load them, hence the load_images method.
NOTE: If needed you can create additional method(s) for loading images. E.g. if you have animations for "left" and "right" movement
I hope this answers your question, if I omitted something please say in comment.