Question

在我在Windows 7 professional 64上运行的以下程序中，我试图允许用户在需要时进行干预（通过内部while循环）并导致外部while循环重复一个动作。否则，内部while循环将超时，程序将继续畅通无阻：

import msvcrt
import time

decision = 'do not repeat' # default setting

for f in ['f1', 'f2', 'f3']:

    print ('doing some prepartory actions on f')

    while True: # outer while loop to allow repeating actions on f

        print ('doing some more actions on f')

        t0 = time.time()
        while time.time() - t0 < 10:        # inner while loop to allow user to intervene 
            if msvcrt.kbhit():              # and repeat actions by pressing ENTER if
                if msvcrt.getch() == '\r':  # needed or allow timeout continuation
                    decision = "repeat"
                    break
                else:
                    break
            time.sleep(0.1)

        if decision == "repeat":
            print ("Repeating f in the outer while loop...")
            continue

        else:
            break

    print ('doing final actions on f in the for loop')

然而，内循环的用户输入部分（按ENTER重复）不起作用，我不知道原因。我从提供的解决方案here中提出了自己的想法。有关如何使其发挥作用的任何想法？

Answer 1

您比较变量决策和字符串＆＃34;重复＆＃34;在您的内循环中，因为您正在使用==运算符。您应该使用=来为变量赋值：

decision = 'repeat'

Answer 2

我现在设法解决了这个问题。 kbhit进程在我正在使用的IDLE（Wing IDE）中不起作用，但是如果从命令提示符调用则可以工作（这可能适用于@eryksun所说的，适用于所有IDLE而不仅仅是Wing）。我发现的另一个问题是getch()进程没有做我需要的，我必须使用返回unicode的getwch()。再进行一次小调整（使用decision默认decision = 'Reset decision to not repeat'，代码现在处于良好的工作状态：

import msvcrt
import time

decision = 'do not repeat' # default setting

for f in ['f1', 'f2', 'f3']:

    print ('doing some prepartory actions on f')

    while True: # outer while loop to allow repeating actions on f

        print ('doing some more actions on f')

        t0 = time.time()
        while time.time() - t0 < 10:        # inner while loop to allow user to intervene 
            if msvcrt.kbhit():              # and repeat actions by pressing ENTER if
                if msvcrt.getchw() == '\r': # needed or allow timeout continuation
                    decision = "repeat"
                    break
                else:
                    break
            time.sleep(0.5)

        if decision == "repeat":
            print ("Repeating f in the outer while loop...")
            decision = 'Reset decision to not repeat'
            continue

        else:
            break

    print ('doing final actions on f in the for loop')

在Python循环中重复超时或用户输入

2 个答案: