Python 3定时输入

Question

我希望能做的是使用输入问一个用户一个问题。例如：

print('some scenario') 
prompt = input("You have 10 seconds to choose the correct answer...\n") 

，然后如果时间流逝打印像

print('Sorry, times up.') 

任何指着我的方向是正确的帮助将不胜感激。

Answer 1

有趣的问题，这似乎工作：

import time 
from threading import Thread 

answer = None 

def check(): 
    time.sleep(2) 
    if answer != None: 
     return 
    print "Too Slow" 

Thread(target = check).start() 

answer = raw_input("Input something: ") 

Answer 2

如果可以接受阻塞主线程，当用户没有提供一个答案：

from threading import Timer 

timeout = 10 
t = Timer(timeout, print, ['Sorry, times up']) 
t.start() 
prompt = "You have %d seconds to choose the correct answer...\n" % timeout 
answer = input(prompt) 
t.cancel() 

否则，你可以使用@Alex Martelli's answer （修改为Python 3）在Windows（未测试）：

import msvcrt 
import time 

class TimeoutExpired(Exception): 
    pass 

def input_with_timeout(prompt, timeout, timer=time.monotonic): 
    sys.stdout.write(prompt) 
    sys.stdout.flush() 
    endtime = timer() + timeout 
    result = [] 
    while timer() < endtime: 
     if msvcrt.kbhit(): 
      result.append(msvcrt.getwche()) #XXX can it block on multibyte characters? 
      if result[-1] == '\n': #XXX check what Windows returns here 
       return ''.join(result[:-1]) 
     time.sleep(0.04) # just to yield to other processes/threads 
    raise TimeoutExpired 

用法：

try: 
    answer = input_with_timeout(prompt, 10) 
except TimeoutExpired: 
    print('Sorry, times up') 
else: 
    print('Got %r' % answer) 

在Unix上你可以尝试：

import select 
import sys 

def input_with_timeout(prompt, timeout): 
    sys.stdout.write(prompt) 
    sys.stdout.flush() 
    ready, _, _ = select.select([sys.stdin], [],[], timeout) 
    if ready: 
     return sys.stdin.readline().rstrip('\n') # expect stdin to be line-buffered 
    raise TimeoutExpired 

或者：

import signal 

def alarm_handler(signum, frame): 
    raise TimeoutExpired 

def input_with_timeout(prompt, timeout): 
    # set signal handler 
    signal.signal(signal.SIGALRM, alarm_handler) 
    signal.alarm(timeout) # produce SIGALRM in `timeout` seconds 

    try: 
     return input(prompt) 
    finally: 
     signal.alarm(0) # cancel alarm