python-2.7 - 如何让计时器与 Python 中的其他代码同时运行？

Question

我正在为我朋友的班级做一个简单的数学测试。学生将只有 45 秒的时间来解决每个答案。有没有办法制作一个计时器，它会在其余代码运行的同时计数，并且当它达到 45 次停止时？

测试看起来像这样：

test = raw_input("How much is 62x5-23?")
if test == '287':
    print "Well done!"

Answer 1

这是我曾经使用过的一些代码（从网络上的某些页面上取下来，现在在域名抢注者手中，因此遗憾的是，没有信用到期的信用）：

import signal

class TimeoutException(Exception):
    pass

def timeout(timeout_time, default = None):
    def timeout_function(f):
        def f2(*args, **kwargs):
            def timeout_handler(signum, frame):
                raise TimeoutException()

            old_handler = signal.signal(signal.SIGALRM, timeout_handler)
            signal.alarm(timeout_time) # triger alarm in timeout_time seconds
            try:
                retval = f(*args, **kwargs)
            except TimeoutException, e:
                if default == None:
                    raise e
                return default
            finally:
                signal.signal(signal.SIGALRM, old_handler)
            signal.alarm(0)
            return retval
        return f2
    return timeout_function

# use like this:
@timeout(45)
def run():
    test = raw_input("How much is 62x5-23? ")
    if test == '287':
        print "Well done!"

# alternatively, pass a value that will be returned when the timeout is reached:
@timeout(45, False)
def run2():
    test = raw_input("How much is 62x5-23? ")
    if test == '287':
        print "Well done!"

if __name__ == '__main__':
    try:
        run()
    except TimeoutException:
        print "\nSorry, you took too long."

    # alternative call:
    if run2() == False:
        print "\nSorry, you took too long."

编辑：可能仅适用于 Unix 类型的操作系统。