python - How do I move a laser bullet in a top down shooter in a certain direction? -

i making game in pygame requires player defend earth aliens attacking it. player controlled arrow keys , spacebar used shoot. far working fine except lasers. when fire laser, wish them move in direction player facing.

here lazer class:

class lazer(pygame.sprite.sprite):     def __init__(self):         super(lazer, self).__init__()         self.image = pygame.image.load('lazer.png')         self.rect = self.image.get_rect()     def update1(self):         keyy = pygame.key.get_pressed()         speed = 30         if keyy[pygame.k_up]:             self.rect.y -= speed          elif keyy[pygame.k_down]:             self.rect.y += speed         if keyy[pygame.k_right]:             self.rect.x += speed         elif keyy[pygame.k_left]:             self.rect.x -= speed 

so far laser moves when player presses arrow key. if player stops pressing arrow key, laser stop moving , if player moves in different direction, laser move in direction.

here full game code:

while gameon == true:     player1.background(gamedisplay)     if len(enemyaliens) < 1:         pygame.time.delay(3000)         wave = wave + 1         diff = diff + wave         in range(diff):             block = aliens()             block.rect.y = random.randrange(200, displayheight-10)             block.rect.x = random.randrange(110, displaywidth-10)             enemyaliens.add(block)             all_sprites.add(block)     event in pygame.event.get():         if event.type == pygame.quit:             pygame.quit()             quit         if event.type == pygame.keydown:             if event.key == pygame.k_space:                 keyy = pygame.key.get_pressed()                 print(direction)                 lazer1 = lazer()                 lazer1.rect.y = player1.rect.y                 lazer1.rect.x = player1.rect.x                 all_sprites.add(lazer1)                 lazer_list.add(lazer1)     lazer1 in lazer_list:         block_hit_list = pygame.sprite.spritecollide(lazer1, enemyaliens, true)         block in block_hit_list:             lazer_list.remove(lazer1)             all_sprites.remove(lazer1)             score += 1             print(score)         if lazer1.rect.y<-10 or lazer1.rect.y > displayheight + 10 or lazer1.rect.x < -10 or lazer1.rect.x > displaywidth +10:             lazer_list.remove(lazer1)             all_sprites.remove(lazer1)     block in enemyaliens:         speed = 3         if block.rect.x > 115:             block.rect.x -= speed         elif block.rect.x < 115:             block.rect.x += speed         if block.rect.y < 91:             block.rect.y += speed         elif block.rect.y > 91:             block.rect.y -= speed         col = pygame.sprite.collide_rect(earth1,block)         if col == true:             all_sprites.remove(block)             enemyaliens.remove(block)             earth_health -= 10     pl in playerlist:         key = pygame.key.get_pressed()         speed = 6         direction = "w"                   if key[pygame.k_up]:             pl.rect.y -= speed             direction = "u"         elif key[pygame.k_down]:             pl.rect.y += speed             direction = "d"         if key[pygame.k_right]:             pl.rect.x += speed             direction = "r"         elif key[pygame.k_left]:             pl.rect.x -= speed             direction = "l"     if earth_health == 0 or earth_health < 0:         if score > highscore:             savehs(score)         gameon = false       healthbars(earth_health)     all_sprites.update()     all_sprites.draw(gamedisplay)     playerlist.draw(gamedisplay)     pygame.display.update() 

how can laser move in direction player moving, , not move along player?