python 3.x - Advice on my pong code -

i doing clone of pong. barebone version of pong. , nice if guys me refine it. doing learning exercise, have kept basic functions.

import time import pygame  done = false pygame.init() myfont = pygame.font.sysfont("monospace", 15)  screen_size = [320,240]  white = [255,255,255] black = [0,0,0]  gutter = 10 score_1 = 0 score_2 = 0 ball_pos = [160,120] ball_vel = [1,1] paddle_1 = [0,0] paddle_2 = [screen_size[0]-5,0] vel_1 = [0,0] vel_2 = [0,0] p1 = false p2 = false  screen = pygame.display.set_mode(screen_size) pygame.display.set_caption("mygame")    while not done:     time.sleep(0.02)     screen.fill(black)      event in pygame.event.get():         if event.type == pygame.quit:             done = true          if event.type == pygame.keydown:              if pygame.key.get_pressed()[pygame.k_down]:                 vel_2[1] += 2                 p1 = true             if pygame.key.get_pressed()[pygame.k_up]:                     p1 = true                 vel_2[1] -= 2             if pygame.key.get_pressed()[pygame.k_s]:                 p2 = true                 vel_1[1] += 2             if pygame.key.get_pressed()[pygame.k_w]:                 p2 = true                 vel_1[1] -= 2          if event.type == pygame.keyup:             if(p1):                 vel_2 = [0,0]                 p1 = false             if (p2):                 vel_1 = [0,0]                 p2 = false      if ball_pos[1] in  range(paddle_1[1],paddle_1[1]+30) , ball_pos[0] in  range(0,gutter+10) :         ball_vel[0] *= -1     if ball_pos[1] in range(paddle_2[1],paddle_2[1]+30) , ball_pos[0] in  range(310,320):         ball_vel[0] *= -1      if ball_pos[0] > 320:         score_1 += 1          ball_pos = [160,120]     if ball_pos[0] < 5:         score_2 += 1          ball_pos = [160,120]     if ball_pos[1] > 230 or ball_pos[1] < 5:         ball_vel[1] *= -1      paddle_1[0] += vel_1[0]     paddle_1[1] += vel_1[1]     paddle_2[0] += vel_2[0]     paddle_2[1] += vel_2[1]      ball_pos[0] += ball_vel[0]     ball_pos[1] += ball_vel[1]   ##    pygame.draw.line(screen,white,(gutter,0),(gutter,screen_size[1])) ##    pygame.draw.line(screen,white,(screen_size[0]-gutter,0),(screen_size[0]-gutter,screen_size[1]))     pygame.draw.line(screen,white,(screen_size[0]/2,0),(screen_size[0]/2,screen_size[1]),1)     pygame.draw.circle(screen,white,ball_pos,10,0)     pygame.draw.line(screen,white,[paddle_1[0]+5,paddle_1[1]],[paddle_1[0]+5,paddle_1[1]+50],gutter)     pygame.draw.line(screen,white,paddle_2,[paddle_2[0],paddle_2[1]+50],gutter)     label_1 = myfont.render(str(score_1), 1, (255,255,0))     label_2 = myfont.render(str(score_2), 1, (255,255,0))     screen.blit(label_1, (100, 100))     screen.blit(label_2, (220, 100))      pygame.display.flip()     pygame.quit() 

there few things should improve in code:

1) constants vs variables

when define

white = [255,255,255] black = [0,0,0] 

you should instead do:

white = (255,255,255) black = (  0,  0,  0) 

constants should created tuples not mistakenly change values. also, since ever read constant , never change value tuple more appropriate. runs faster

2) creating classes

whenever make game, recommended create objects classes. in case, have classes such player , ball. in these classes can define functions such update , draw. allow draw object or update location, speed etc single line of code. eg:

player.update()

player.draw()

ball.draw()

3) time vs timer

instead of using import time, recommend use pygame built-in timer option controlling fps of game. here's example:

timer = pygame.time.clock()

then @ start of while loop, can do:

timer.tick(60) #if want 60 number of frames per second

i know lot take in in end effort more worth , make future game making pygame cleaner.

great resource book

happy pygaming!