[PyGame] How to stop the sprite's movement when it touches the edges of the screen?

[mrmn]

I'd do it this way, check if player's sprite x axis position + player's sprite width is lower than screen width, if it is, then move sprite to the right.
Example in your code:

import pygame
from pygame import *
import sys
 
WIDTH = 600
HEIGHT = 480
FPS = 60
 
# define colors
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)
 
class Player(pygame.sprite.Sprite):
    # sprite for the player
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface((50, 50))
        self.image.fill(GREEN)
        self.rect = self.image.get_rect()
        self.rect.center = (WIDTH / 2, HEIGHT / 2)
 
# initialize pygame and create window
pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("My game")
clock = pygame.time.Clock()
pygame.key.set_repeat(True)
 
all_sprites = pygame.sprite.Group()
player = Player()
all_sprites.add(player)
 
# Game loop
while True:
    # keep loop running at the right speed
    clock.tick(FPS)
    # Process input (events)
    for event in pygame.event.get():
        # check for closing window
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        # Moving sprites with arrow keys or WASD
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_UP or event.key == K_w:
                player.rect.centery -= 5
            elif event.key == pygame.K_DOWN or event.key == K_s:
                player.rect.centery += 5
            elif event.key == pygame.K_LEFT or event.key == K_a:
                player.rect.left -= 5
            elif event.key == pygame.K_RIGHT or event.key == K_d:
                # basically, if (sprite.x + sprite.width < screen.width): sprite.x += 5
                if player.rect.x + player.imange.get_width() < WIDTH:
                    # not sure if methods are correct
                    player.rect.right += 5
 
    # Update
    all_sprites.update()
 
    # Draw / render
    screen.fill(BLACK)
    all_sprites.draw(screen)
    # *after* drawing everything, flip the display
    pygame.display.flip()

I tried it, but this way the sprite only moves upward-right, stops only at the right edge and refuses to move leftward