Object moves off screen

Question

import pygame
#Colors, Allways you need colors!!!!
BLACK = ( 0, 0, 0)
GREEN = ( 0, 255, 0)
WHITE = ( 255, 255, 255)
RED = ( 255, 0, 0)
ORANGE = ( 255, 115, 0)
YELLOW = ( 242, 255, 0)
BROWN = ( 115, 87, 39)
PURPLE = ( 298, 0, 247)
GRAY = ( 168, 168, 168)
PINK = ( 255, 0, 234)
BLUE = ( 0, 0 , 255)
pygame.init()
# Screen
screen = pygame.display.set_mode([700,500])
#Name of thewindow
pygame.display.set_caption("Trial to make PONG")
# Any variables!

x_speed = 0
y_speed = 0

x_coord = 10
y_coord = 250

x = 670
y = 250
other_speed = 0
other_speed2 = 0

rect_x = 50
rect_y = 50

rect_change_x = 5
rect_change_y = 5
clock = pygame.time.Clock()
#Sounds,maybe needed?

#Main Loop__________

done = False

while not done:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True

             # User pressed down on a key
        elif event.type == pygame.KEYDOWN:
            # Figure out if it was an arrow key. If so
            # adjust speed.

            if event.key == pygame.K_UP:
                y_speed = -5
            elif event.key == pygame.K_DOWN:
                y_speed = 5
            elif event.key == pygame.K_w:
                other_speed2 = -5
            elif event.key == pygame.K_s:
                other_speed2 = 5

    # User let up on a key
        elif event.type == pygame.KEYUP:
        # If it is an arrow key, reset vector back to zero
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                x_speed = 0
            elif event.key == pygame.K_UP or event.key == pygame.K_DOWN:
                y_speed = 0
            elif event.key == pygame.K_w or event.key == pygame.K_s:
                other_speed2 = 0


# Move the object according to the speed vector.
    x_coord += x_speed
    y_coord += y_speed
    x +=  x_speed
    y +=  other_speed2


    screen.fill(BLACK)

    pygame.draw.rect(screen,BLUE,[x_coord,y_coord,20,60])
    pygame.draw.rect(screen,YELLOW,[x,y,20,60])

    if x > 650 or x < 0:

    # Draw the rectangle
    pygame.draw.ellipse(screen, BLUE, [rect_x, rect_y, 50, 50])

    # Move the rectangle starting point
    rect_x += rect_change_x
    rect_y += rect_change_y

    if rect_x > 650 or rect_x < 0:
        rect_change_x = rect_change_x * -1
    if rect_y > 450 or rect_y < 0:
        rect_change_y = rect_change_y * -1





    pygame.display.flip()
    clock.tick(60)

pygame.quit()

Ok so I have 2 paddles in this pong game called Blue and yellow rectangle. I can move them but they move off the screen. How do I prevent that. Iv looked online but nothing seems to be working. I thought about putting rectangles around the screen to make a collision point argument where when the Blue/Yellow paddle hit it they won't move any further, but im not sure how to do that with ought ruining the code? Thank you for your help..

Answer 1

You should check to see if it's off the edge of the screen before you change the y coordinate. See

if y_coord + y_speed >= 0 and y_coord + y_speed + 60 <= 500:
    y_coord += y_speed

Though as you can see it can get a little confusing to use numbers, which is why you should avoid hard-coding. It's better to have a display_height, display_width, and y_speed variable. Basically, outside of initializing variables, you should only have 0s as numbers. Also, note what happens when you leave out + y_speed in the if statement.