Question

我正在尝试制作游戏，在这个游戏中我想在0到-100之间的随机Y位置制作100个对象。

但是当我尝试random.randrange(0, -100)时，它返回了一条错误消息：

Traceback (most recent call last):
  File "main.py", line 144, in <module>
    main();
  File "main.py", line 30, in main
    setGlobalValues();
  File "main.py", line 23, in setGlobalValues
    food = Food();
  File "main.py", line 92, in __init__
    self.y = random.randrange(0, -100);
  File "C:\Users\sidna\AppData\Local\Programs\Python\Python36-32\lib\random.py", line 198, in randrange
    raise ValueError("empty range for randrange() (%d,%d, %d)" % (istart, istop, width))
ValueError: empty range for randrange() (0,-100, -100)

以下是完整的代码：

PYTHON

# IMPORTS
import pygame, random;

# GLOBALS
global screen, displayW, displayH;
global clock, FPS;
global end, food, player;

# SETGLOBALVALUES
def setGlobalValues():
    global screen, displayW, displayH;
    global clock, FPS;
    global end, food, player;

    displayW = 800;
    displayH = 600;
    screen = pygame.display.set_mode((displayW, displayH));

    clock = pygame.time.Clock();
    FPS = 60;

    end = False;
    food = Food();
    player = Player();

# MAIN
def main():
    pygame.init();

    setGlobalValues();
    setup();
    gameLoop();
    quitGame();

# GAMELOOP
def gameLoop():
    global end, player;

    while(not end):
        for event in pygame.event.get():
            # ONCLICK QUIT
            if(event.type == pygame.QUIT):
                end = True;

            # KEYDOWN
            if(event.type == pygame.KEYDOWN):
                if(event.key == pygame.K_LEFT):
                    player.velX -= 1;
                if(event.key == pygame.K_RIGHT):
                    player.velX += 1;

            # KEYUP
            if(event.type == pygame.KEYUP):
                if(event.key == pygame.K_LEFT):
                    player.velX = 0;
                if(event.key == pygame.K_RIGHT):
                    player.velX = 0;

        draw();
        animate();


# DRAW
def draw():
    global screen, food, player;

    # fill background
    screen.fill((255, 255, 255));

    food.draw();

    # update
    pygame.display.update();

# ANIMATE
def animate():
    global food, player;

    food.animate();
    player.animate();

# COLLISION
def collision():
    pass;

# CLASSES
class Food():
    def __init__(self, x=0, y=0, w=0, h=0, velY=0, color=()):
        global displayW;

        self.x = random.randrange(0, displayW);
        self.y = random.randrange(0, -100);
        self.w = 20;
        self.h = 20;
        self.velY = 0.7;
        self.color = (255, 0, 0);

    def draw(self):
        global screen;

        for amount in range(100):
            pygame.draw.rect(screen, self.color, (self.x, self.y, self.w, self.h));

    def animate(self):
        self.y += self.velY;

    def collision(self):
        global displayW, displayH;

        pass;

class Player():
    def __init__(self, x=0, y=0, velX=0, velY=0, w=0, h=0, color=()):
        global displayW, displayH;

        self.w = 20;
        self.h = 20;
        self.x = displayW / 2 - self.w / 2;
        self.y = displayH - 100;
        self.velX = 0;
        self.velY = 0;
        self.color = (0, 0, 0);

    def draw(self):
        global screen;

        pygame.draw.ellipse(screen, self.color, (self.x, self.y, self.w, self.h));

    def animate(self):
        self.x += self.velX;
        self.y += self.velY;

# SETUP
def setup():
    pygame.display.set_caption("Food Catcher");

# QUIT GAME
def quitGame():
    pygame.quit();
    quit();

# CALL MAIN
if(__name__ == "__main__"):
    main();

Answer 1

smaller number should be the first argument（如果您使用多个参数）：

import random
random.randrange(-100, 1)

第二个参数未包含在内，因此如果您希望0作为可能的结果，则需要将其设置为1。

但是，如果您实际上没有使用step - 参数，那么还有random.randint：

random.randint(-100, 0)  # randint includes the "stop"!

Answer 2

介于-100和0之间的随机数与0到100之间的随机数乘以-1

/* connect to gmail */
$hostname = '{imap.gmail.com:993/imap/ssl}INBOX';
$username = 'X';
$password = 'X';
/* try to connect */
$inbox = imap_open($hostname,$username,$password) or die('Cannot connect to Gmail: ' . imap_last_error());
/* grab emails */
$emails = imap_search($inbox,'ALL');
/* if emails are returned, cycle through each... */
if($emails) {        
        /* begin output var */
        $output = '';        
        /* put the newest emails on top */
        rsort($emails);        
        /* for every email... */
        foreach($emails as $email_number) {                
                /* get information specific to this email */
                $overview = imap_fetch_overview($inbox,$email_number,0);
                $message = imap_fetchbody($inbox,$email_number,2);                
                /* output the email header information */
                $output.= '<div class="toggler '.($overview[0]->seen ? 'read' : 'unread').'">';
                $output.= '<span class="subject">'.$overview[0]->subject.'</span> ';
                $output.= '<span class="from">'.$overview[0]->from.'</span>';
                $output.= '</div>';

        }        
        echo $test , $test , $output;
}
imap_close($inbox);

或

-1*random.randrange(100)

如何在random.rand范围中使用负数

2 个答案: