Python - How To Interact With Class In Different Method

I am having an issue with interacting with a classes variables from within a method. I want to change the position of an object in pygame. This has to be done in a method as i use

Solution 1:

You can't simply call Enemy.X because Enemy is a class definition. In the other line you have for enemy in enemy_list which calls upon all the instances of Enemy (instances are different and here they are enemy with a lowercase). To follow a player you would first need a player in your code! I would also recommend you don't use a new thread for each functionality of your game. You can throw in your logic to move enemies into your normal game loop which already has its own thread.

import pygame
import threading
from random import randint
from time import sleep

pygame.init()
window = pygame.display.set_mode((900, 900))
bg = pygame.image.load("Background.png").convert()

classEnemy:
    def__init__(self):
        self.W = 50
        self.H = 50
        self.X = 420
        self.Y = 850
        self.speed = 1classPlayer: # make a new class so players can have better statsdef__init__(self):
        self.W = 50
        self.H = 50
        self.X = 300
        self.Y = 300
        self.speed = 10defGameplay():
    global enemy_list
    global player
    whileTrue:
        window.blit(bg, [0, 0])
        pygame.draw.rect(window, (255, 255, 255), (player.X, player.Y, player.W, player.H))
        for enemy in enemy_list:
            if enemy.X > player.X:
                enemy.X = enemy.X - enemy.speed
            else:
                enemy.X = enemy.X + enemy.speed
            if enemy.Y > player.Y:
                enemy.Y = enemy.Y - enemy.speed
            else:
                enemy.Y = enemy.Y + enemy.speed
            pygame.draw.rect(window, (255, 50, 49), (enemy.X, enemy.Y, enemy.W, enemy.H))
        pygame.display.update()

defEnemySpawn():
    global enemy_list
    whileTrue: # make enemies foreverprint("Spawned an enemy")
        enemy_list.append(Enemy()) # make an instance of our class
        sleep(randint(1, 5))

if __name__ == "__main__":
    player = Player() # notice the difference in capitalization!
    enemy_list = [] # to maintain records of all enemies made
    game_thread = threading.Thread(target=Gameplay)
    game_thread.start()
    enemy_spawner_thread = threading.Thread(target=EnemySpawn)
    enemy_spawner_thread.start()

As @furas notes though you may be better off with just a mainloop that has sub-functions to check all these things! I suspect the next thing you would want to do is implement a keyboard listener to allow your player to move.

Also note that at this point we have two classes that look very similar. We will probably benefit from having a base class (let's say Human) that both these classes inherit from. In this way we can add a trait to both classes with a single line of code. The child classes can still overwrite the values supplied though if needed:

import pygame
import threading
from random import randint
from time import sleep

pygame.init()
window = pygame.display.set_mode((900, 900))
bg = pygame.image.load("Video & Image Processing/Image Processing/InputImage.jpg").convert()

classHuman:
    def__init__(self):
        self.W = 50
        self.H = 50
        self.X = 420
        self.Y = 850
        self.speed = 1classEnemy(Human): # inherit Humandef__init__(self):
        Human.__init__(self) # get all traits a Human hasclassPlayer(Human): # inherit Humandef__init__(self):
        Human.__init__(self) # get all traits a Human has
        self.X = 300# overwrite specific traits
        self.Y = 300defGameplay():
    global enemy_list
    global player
    whileTrue:
        window.blit(bg, [0, 0])
        pygame.draw.rect(window, (255, 255, 255), (player.X, player.Y, player.W, player.H))
        for enemy in enemy_list:
            if enemy.X > player.X:
                enemy.X = enemy.X - enemy.speed
            else:
                enemy.X = enemy.X + enemy.speed
            if enemy.Y > player.Y:
                enemy.Y = enemy.Y - enemy.speed
            else:
                enemy.Y = enemy.Y + enemy.speed
            pygame.draw.rect(window, (255, 50, 49), (enemy.X, enemy.Y, enemy.W, enemy.H))
        pygame.display.update()

defEnemySpawn():
    global enemy_list
    whileTrue: # make enemies foreverprint("Spawned an enemy")
        enemy_list.append(Enemy()) # make an instance of our class
        sleep(randint(1, 5))


if __name__ == "__main__":
    player = Player() # notice the difference in capitalization!
    enemy_list = [] # to maintain records of all enemies made
    game_thread = threading.Thread(target=Gameplay)
    game_thread.start()
    enemy_spawner_thread = threading.Thread(target=EnemySpawn)
    enemy_spawner_thread.start()

Solution 2:

You are trying to reach X as it is static member of the Enemy class, which is wrong as it is attribute of class instance (object). To reach it you need to use object, which is what you keep stored in enemy_list list.