你用python写出代码来，用pycharm软件，解释器为3.7版本

好的，以下是用Python实现的乓球游戏代码，你可以在PyCharm软件上运行。注意，代码中的注释可以帮助你理解每个函数和变量的作用。

import pygame
import sys

# 定义游戏屏幕尺寸
WIN_WIDTH = 800
WIN_HEIGHT = 600

# 定义乒乓球和球拍的尺寸
BALL_SIZE = 20
PAD_WIDTH = 100
PAD_HEIGHT = 20

# 定义球拍的移动速度
PAD_SPEED = 5

# 定义球拍与屏幕边缘之间的距离
PAD_MARGIN = 20

# 定义球拍颜色和乒乓球颜色
PAD_COLOR = (255, 255, 255)
BALL_COLOR = (255, 255, 255)

# 定义字体大小和颜色
FONT_SIZE = 36
FONT_COLOR = (255, 255, 255)

# 初始化pygame
pygame.init()

# 设置游戏屏幕
screen = pygame.display.set_mode((WIN_WIDTH, WIN_HEIGHT))

# 设置游戏标题
pygame.display.set_caption('Ping Pong Game')

# 创建字体
font = pygame.font.SysFont(None, FONT_SIZE)


def draw_text(text, x, y):
    """绘制文本"""
    text_obj = font.render(text, True, FONT_COLOR)
    text_rect = text_obj.get_rect()
    text_rect.centerx = x
    text_rect.centery = y
    screen.blit(text_obj, text_rect)


def draw_ball(ball_x, ball_y):
    """绘制乒乓球"""
    pygame.draw.circle(screen, BALL_COLOR, (ball_x, ball_y), BALL_SIZE // 2)


def draw_paddle(paddle_x, paddle_y):
    """绘制球拍"""
    pygame.draw.rect(screen, PAD_COLOR, (paddle_x, paddle_y, PAD_WIDTH, PAD_HEIGHT))


def move_paddle(paddle_x, paddle_speed):
    """移动球拍"""
    keys = pygame.key.get_pressed()
    if keys[pygame.K_LEFT]:
        paddle_x -= paddle_speed
    if keys[pygame.K_RIGHT]:
        paddle_x += paddle_speed
    # 限制球拍的移动范围
    if paddle_x < PAD_MARGIN:
        paddle_x = PAD_MARGIN
    if paddle_x > WIN_WIDTH - PAD_MARGIN - PAD_WIDTH:
        paddle_x = WIN_WIDTH - PAD_MARGIN - PAD_WIDTH
    return paddle_x


def move_ball(ball_x, ball_y, ball_speed_x, ball_speed_y, paddle_x, paddle_y):
    """移动乒乓球"""
    ball_x += ball_speed_x
    ball_y += ball_speed_y
    # 判断乒乓球是否碰到左右边缘
    if ball_x <= BALL_SIZE // 2 or ball_x >= WIN_WIDTH - BALL_SIZE // 2:
        ball_speed_x = -ball_speed_x
    # 判断乒乓球是否碰到上边缘
    if ball_y <= BALL_SIZE // 2:
        ball_speed_y = -ball_speed_y
    # 判断乒乓球是否碰到球拍
    if ball_y >= paddle_y - BALL_SIZE // 2 and ball_x >= paddle_x - BALL_SIZE // 2 and ball_x <= paddle_x + PAD_WIDTH + BALL_SIZE // 2:
        ball_speed_y = -ball_speed_y
    # 判断乒乓球是否落到下边缘
    if ball_y >= WIN_HEIGHT - BALL_SIZE // 2:
        return -1, ball_speed_x, ball_speed_y
    else:
        return ball_x, ball_speed_x, ball_speed_y


def play_game():
    """游戏主循环"""
    ball_x = WIN_WIDTH // 2
    ball_y = WIN_HEIGHT // 2
    ball_speed_x = 5
    ball_speed_y = 5
    paddle_x = WIN_WIDTH // 2 - PAD_WIDTH // 2
    paddle_y = WIN_HEIGHT - PAD_MARGIN - PAD_HEIGHT
    paddle_speed = PAD_SPEED
    score = 0

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()
            # 按Esc键退出游戏
            if event.type == pygame.KEYDOWN and event.key == pygame.K_ESCAPE:
                pygame.quit()
                sys.exit()
            # 按enter键开始下一轮游戏
            if event.type == pygame.KEYDOWN and event.key == pygame.K_RETURN:
                return

        # 移动球拍
        paddle_x = move_paddle(paddle_x, paddle_speed)

        # 移动乒乓球
        ball_x, ball_speed_x, ball_speed_y = move_ball(ball_x, ball_y, ball_speed_x, ball_speed_y, paddle_x, paddle_y)
        if ball_x == -1:
            score += 1
            ball_x = WIN_WIDTH // 2
            ball_y = WIN_HEIGHT // 2
            ball_speed_x = 5
            ball_speed_y = 5

        # 绘制游戏界面
        screen.fill((0, 0, 0))
        draw_ball(ball_x, ball_y)
        draw_paddle(paddle_x, paddle_y)
        draw_text("Score: {}".format(score), WIN_WIDTH // 2, FONT_SIZE)
        pygame.display.update()


# 游戏开始界面
while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        # 按Esc键退出游戏
        if event.type == pygame.KEYDOWN and event.key == pygame.K_ESCAPE:
            pygame.quit()
            sys.exit()

    # 绘制游戏开始界面
    screen.fill((0, 0, 0))
    draw_text("Ping Pong Game", WIN_WIDTH // 2, WIN_HEIGHT // 2 - FONT_SIZE)
    draw_text("Press '1' for single player mode", WIN_WIDTH // 2, WIN_HEIGHT // 2 + FONT_SIZE)
    draw_text("Press '2' for double player mode", WIN_WIDTH // 2, WIN_HEIGHT // 2 + 2 * FONT_SIZE)
    pygame.display.update()

    # 选择游戏模式
    keys = pygame.key.get_pressed()
    if keys[pygame.K_1]:
        play_game()
        draw_text("You lose", WIN_WIDTH // 2, WIN_HEIGHT // 2 - FONT_SIZE)
        draw_text("Press 'Enter' to play again", WIN_WIDTH // 2, WIN_HEIGHT // 2 + FONT_SIZE)
        pygame.display.update()
        # 按enter键重新开始游戏
        while True:
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    pygame.quit()
                    sys.exit()
                if event.type == pygame.KEYDOWN and event.key == pygame.K_ESCAPE:
                    pygame.quit()
                    sys.exit()
                if event.type == pygame.KEYDOWN and event.key == pygame.K_RETURN:
                    break
            keys = pygame.key.get_pressed()
            if keys[pygame.K_RETURN]:
                break
    elif keys[pygame.K_2]:
        play_game()
        draw_text("Player 2 wins", WIN_WIDTH // 2, WIN_HEIGHT // 2 - FONT_SIZE)
        draw_text("Press 'Enter' to play again", WIN_WIDTH // 2, WIN_HEIGHT // 2 + FONT_SIZE)
        pygame.display.update()
        # 按enter键重新开始游戏
        while True:
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    pygame.quit()
                    sys.exit()
                if event.type == pygame.KEYDOWN and event.key == pygame.K_ESCAPE:
                    pygame.quit()
                    sys.exit()
                if event.type == pygame.KEYDOWN and event.key == pygame.K_RETURN:
                    break
            keys = pygame.key.get_pressed()
            if keys[pygame.K_RETURN]:
                break