我的跨平台解决方案

def input_process(stdin_fd, sq, str):
    sys.stdin = os.fdopen(stdin_fd)
    try:
        inp = input (str)
        sq.put (True)
    except:
        sq.put (False)

def input_in_time (str, max_time_sec):
    sq = multiprocessing.Queue()
    p = multiprocessing.Process(target=input_process, args=( sys.stdin.fileno(), sq, str))
    p.start()
    t = time.time()
    inp = False
    while True:
        if not sq.empty():
            inp = sq.get()
            break
        if time.time() - t > max_time_sec:
            break
    p.terminate()
    sys.stdin = os.fdopen( sys.stdin.fileno() )
    return inp

from func_timeout import FunctionTimedOut, func_timeout

try:
   ans = func_timeout(5, lambda: int(input('What is the sum of 2 and 3?\n')))
   print(ans)
except FunctionTimedOut:
   print(5)

func_timeout会返回其参数中方法的值，本例中为question()函数。它还允许传递其他函数需要的参数（参见文档）。 如果经过设置的时间（此处为5秒），则会引发TimedOutException并运行except块中的代码。

from threading import Thread
import time


def get_input():
    while True:
        print(input('> '))


t1 = Thread(target=get_input)
t1.setDaemon(True)
t1.start()
time.sleep(3)
print('program exceeds')

很简单，只需设置一个新的守护线程，并设置一个你想要的睡眠时间作为超时。我认为这很容易理解 XD

import subprocess  
subprocess.call('timeout /T 30')

对我有效的修改过的iperov答案（python3 win10 2019-12-09）

对iperov的更改：

• 将str替换为sstr，因为str是Python中的一个函数

• 添加导入

• 在while循环中添加sleep以降低CPU使用率 (?)

• 添加if name=='main': #在Windows上需要多进程

  import sys, os, multiprocessing, time

  def input_process(stdin_fd, sq, sstr):
      sys.stdin = os.fdopen(stdin_fd)
      try:
          inp = input(sstr)
          sq.put(True)
      except:
          sq.put(False)
  
  def input_in_time(sstr, max_time_sec):
      sq = multiprocessing.Queue()
      p = multiprocessing.Process(target=input_process, args=( sys.stdin.fileno(), sq, sstr))
      p.start()
      t = time.time()
      inp = False
      while True:
  
          if not sq.empty():
              inp = sq.get()
              break
          if time.time() - t > max_time_sec:
              break
  
          tleft=int( (t+max_time_sec)-time.time())
          if tleft<max_time_sec-1 and tleft>0:
              print('\n  ...剩余时间 '+str(tleft)+'秒\n命令：')
  
          time.sleep(2)
  
      p.terminate()
      sys.stdin = os.fdopen( sys.stdin.fileno() )
      return inp
  
  if __name__=='__main__':
      input_in_time("命令：", 17)
  

$ pip install inputimeout

from inputimeout import inputimeout, TimeoutOccurred
try:
    something = inputimeout(prompt='>>', timeout=5)
except TimeoutOccurred:
    something = 'something'
print(something)

import datetime

def custom_time_input(msg, seconds):
    try:
        print(msg)
        # current time in seconds
        current_time = datetime.datetime.now()
        time_after = current_time + datetime.timedelta(seconds=seconds)
        while datetime.datetime.now() < time_after:
            print("Time left: ", end="")
            print(time_after - datetime.datetime.now(), end="\r")
            time.sleep(1)
        print("\n")
        return True
    except KeyboardInterrupt:
        return False

res = custom_time_input("If you want to create a new config file PRESS CTRL+C within 20 seconds!", 20)
if res:
    pass # nothing changed
else:
    pass # do something because user pressed ctrl+c

import sys
import subprocess


def switch():
    if len(sys.argv) == 1:
        main()
    elif sys.argv[1] == "inp":
        print(input(''))
    else:
        print("Wrong arguments:", sys.argv[1:])


def main():
    passw = input_timed('You have 10 seconds to enter password:', timeout=10)
    if passw is None:
        print("Time's out! You explode!")
    elif passw == "PasswordShmashword":
        print("H-h-how did you know you h-h-hacker")
    else:
        print("I spare your life because you at least tried")


def input_timed(*args, timeout, **kwargs):
    """
    Print a message and await user input - return None if timedout
    :param args: positional arguments passed to print()
    :param timeout: number of seconds to wait before returning None
    :param kwargs: keyword arguments passed to print()
    :return: user input or None if timed out
    """
    print(*args, **kwargs)
    try:
        out: bytes = subprocess.run(["python", sys.argv[0], "inp"], capture_output=True, timeout=timeout).stdout
    except subprocess.TimeoutExpired:
        return None
    return out.decode('utf8').splitlines()[0]


switch()

我正在使用一个外部工具inputimeout。源代码可在github上找到。我知道这是一个外部工具，但它非常简单实用。

安装完工具后，请使用以下代码：

from inputimeout import inputimeout, TimeoutOccurred
try:
    something = inputimeout(prompt='>>', timeout=5)
except TimeoutOccurred:
    something = 'No input.'
print(something)

from inputimeout import inputimeout, TimeoutOccurred

def timed_input (user_prompt, timeout=5):
    user_input = ""
    timed_out = False
    try:
        user_input = inputimeout (prompt=user_prompt, timeout=timeout)
    except TimeoutOccurred:
        timed_out = True
    return (timed_out, user_input)

timed_out, user_input = timed_input ("Enter something within 3s... ", timeout=3)

if timed_out:
    print ("You failed to enter anything!")
else:
    print (f"You entered {user_input}")