"如何根据用户输入重新启动程序？"

Question

I'm trying to restart a program using an if-test based on the input from the user.

This code doesn't work, but it's approximately what I'm after:

answer = str(raw_input('Run again? (y/n): '))

if answer == 'n':
   print 'Goodbye'
   break
elif answer == 'y':
   #restart_program???
else:
   print 'Invalid input.'

What I'm trying to do is:

• if you answer y - the program restarts from the top
• if you answer n - the program ends (that part works)
• if you enter anything else, it should print 'invalid input. please enter y or n...' or something, and ask you again for new input.

I got really close to a solution with a "while true" loop, but the program either just restarts no matter what you press (except n), or it quits no matter what you press (except y). Any ideas?

Answer 1

This line will unconditionally restart the running program from scratch:

os.execl(sys.executable, sys.executable, *sys.argv)

Answer 2

Try this:

while True:
    # main program
    while True:
        answer = str(input('Run again? (y/n): '))
        if answer in ('y', 'n'):
            break
        print("invalid input.")
    if answer == 'y':
        continue
    else:
        print("Goodbye")
        break

Answer 3

Using one while loop:

In [1]: start = 1
   ...: 
   ...: while True:
   ...:     if start != 1:        
   ...:         do_run = raw_input('Restart?  y/n:')
   ...:         if do_run == 'y':
   ...:             pass
   ...:         elif do_run == 'n':
   ...:             break
   ...:         else: 
   ...:             print 'Invalid input'
   ...:             continue
   ...: 
   ...:     print 'Doing stuff!!!'
   ...: 
   ...:     if start == 1:
   ...:         start = 0
   ...:         
Doing stuff!!!

Restart?  y/n:y
Doing stuff!!!

Restart?  y/n:f
Invalid input

Restart?  y/n:n

In [2]:

Answer 4

You can do this simply with a function. For example:

def script():
    # program code here...
    restart = raw_input("Would you like to restart this program?")
    if restart == "yes" or restart == "y":
        script()
    if restart == "n" or restart == "no":
        print "Script terminating. Goodbye."
script()

Of course you can change a lot of things here. What is said, what the script will accept as a valid input, the variable and function names. You can simply nest the entire program in a user-defined function (Of course you must give everything inside an extra indent) and have it restart at anytime using this line of code: myfunctionname() . More on this here.

Answer 5

Here's a fun way to do it with a decorator :

def restartable(func):
    def wrapper(*args,**kwargs):
        answer = 'y'
        while answer == 'y':
            func(*args,**kwargs)
            while True:
                answer = raw_input('Restart?  y/n:')
                if answer in ('y','n'):
                    break
                else:
                    print "invalid answer"
    return wrapper

@restartable
def main():
    print "foo"

main()

Ultimately, I think you need 2 while loops. You need one loop bracketing the portion which prompts for the answer so that you can prompt again if the user gives bad input. You need a second which will check that the current answer is 'y' and keep running the code until the answer isn't 'y' .

Answer 6

It is very easy do this

while True:

       #do something

       again = input("Run again? ")

       if 'yes' in again:
              continue
       else:
              print("Good Bye")
              break

Answer 7

I create this program:

import pygame, sys, time, random, easygui

skier_images = ["skier_down.png", "skier_right1.png",
                "skier_right2.png", "skier_left2.png",
                "skier_left1.png"]

class SkierClass(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.image.load("skier_down.png")
        self.rect = self.image.get_rect()
        self.rect.center = [320, 100]
        self.angle = 0

    def turn(self, direction):
        self.angle = self.angle + direction
        if self.angle < -2:  self.angle = -2
        if self.angle >  2:  self.angle =  2
        center = self.rect.center
        self.image = pygame.image.load(skier_images[self.angle])
        self.rect = self.image.get_rect()
        self.rect.center = center
        speed = [self.angle, 6 - abs(self.angle) * 2]
        return speed

    def move(self,speed):
        self.rect.centerx = self.rect.centerx + speed[0]
        if self.rect.centerx < 20:  self.rect.centerx = 20
        if self.rect.centerx > 620: self.rect.centerx = 620

class ObstacleClass(pygame.sprite.Sprite):
    def __init__(self,image_file, location, type):
        pygame.sprite.Sprite.__init__(self)
        self.image_file = image_file
        self.image = pygame.image.load(image_file)
        self.location = location
        self.rect = self.image.get_rect()
        self.rect.center = location
        self.type = type
        self.passed = False

    def scroll(self, t_ptr):
        self.rect.centery = self.location[1] - t_ptr

def create_map(start, end):
    obstacles = pygame.sprite.Group()
    gates = pygame.sprite.Group()
    locations = []
    for i in range(10):
        row = random.randint(start, end)
        col = random.randint(0, 9)
        location = [col * 64 + 20, row * 64 + 20]
        if not (location in locations) :
            locations.append(location)
            type = random.choice(["tree", "flag"])
            if type == "tree": img = "skier_tree.png"
            elif type == "flag": img = "skier_flag.png"
            obstacle = ObstacleClass(img, location, type)
            obstacles.add(obstacle)
    return obstacles

def animate():
    screen.fill([255,255,255])
    pygame.display.update(obstacles.draw(screen))
    screen.blit(skier.image, skier.rect)
    screen.blit(score_text, [10,10])
    pygame.display.flip()

def updateObstacleGroup(map0, map1):
    obstacles = pygame.sprite.Group()
    for ob in map0:  obstacles.add(ob)
    for ob in map1:  obstacles.add(ob)
    return obstacles

pygame.init()
screen = pygame.display.set_mode([640,640])
clock = pygame.time.Clock()
skier = SkierClass()
speed = [0, 6]
map_position = 0
points = 0
map0 = create_map(20, 29)
map1 = create_map(10, 19)
activeMap = 0
obstacles = updateObstacleGroup(map0, map1)
font = pygame.font.Font(None, 50)

a = True

while a:
    clock.tick(30)
    for event in pygame.event.get():
        if event.type == pygame.QUIT: sys.exit()
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                speed = skier.turn(-1)
            elif event.key == pygame.K_RIGHT:
                speed = skier.turn(1)
    skier.move(speed)
    map_position += speed[1]

    if map_position >= 640 and activeMap == 0:
        activeMap = 1
        map0 = create_map(20, 29)
        obstacles = updateObstacleGroup(map0, map1)
    if map_position >=1280 and activeMap == 1:
        activeMap = 0
        for ob in map0:
            ob.location[1] = ob.location[1] - 1280
        map_position = map_position - 1280
        map1 = create_map(10, 19)
        obstacles = updateObstacleGroup(map0, map1)
    for obstacle in obstacles:
        obstacle.scroll(map_position)

    hit = pygame.sprite.spritecollide(skier, obstacles, False)
    if hit:
        if hit[0].type == "tree" and not hit[0].passed:
            skier.image = pygame.image.load("skier_crash.png")
            easygui.msgbox(msg="OOPS!!!")
            choice = easygui.buttonbox("Do you want to play again?", "Play", ("Yes", "No"))
            if choice == "Yes":
                skier = SkierClass()
                speed = [0, 6]
                map_position = 0
                points = 0
                map0 = create_map(20, 29)
                map1 = create_map(10, 19)
                activeMap = 0
                obstacles = updateObstacleGroup(map0, map1)
            elif choice == "No":
                a = False
                quit()
        elif hit[0].type == "flag" and not hit[0].passed:
            points += 10
            obstacles.remove(hit[0])

    score_text = font.render("Score: " + str(points), 1, (0, 0, 0))
    animate()

Link: https://docs.google.com/document/d/1U8JhesA6zFE5cG1Ia3OsTL6dseq0Vwv_vuIr3kqJm4c/edit