如何在没有Tkinter的情况下捕获Python中的Enter键

如果按下回车键，我需要使程序从Python重新开始。我找到了这个问题和解决方案：如何检查回车键是否按python。但是，当我搜索event.keysym时，它似乎与Tkinter有关，但我认为我没有。

当我尝试使用解决方案时，出现错误：

Traceback (most recent call last):
  File "/home/q/Desktop/PigsAndBulls.py", line 52, in <module>
    if event.keysym == 'Return':
NameError: name 'event' is not defined

我是一位完全的新手，刚完成与Coursera的Severance博士的课程。

这是我写的玩猪和公牛的程序。一切都如我所愿。唯一的问题是，如果按下除“输入”按钮以外的任何其他键，则退出程序。

while True: 
    while True:
        word= raw_input("Enter a four letter English word with no repeating letters:  ")
        print
        if len(word) <> 4:
            print "What part of 'four letter word' did you not understand? Try again."
            print
            continue    
        else: break

    guesses = 0

    while True:
        correct = 0
        position = 0
        cnt = 0
        result = 0

        guess= raw_input("Enter a guess:  ")
        guesses = guesses+1
        #print "guessses", guesses 
        for w in guess:
            cnt = cnt+1
            #print "cnt", cnt
            position=0
            for g in word:
                position=position+1
                #print "position", position
                if g == w:
                    correct = correct+1
                    if position == cnt:
                        result = result+1
                        #print "result", result
        print
        print "Number correct:", correct
        print "Number in the right position:", result
        print
        if correct<>4 and result<>4:
            print "Give me another guess" 
            print        
            continue
        elif correct == 4 and result == 4:
            print
            print "YOU WIN"
            print
            print "It took you", guesses, " guesses to get it right"
            print
            break

    answer= raw_input("press  ""enter"" to play again")
    if event.keysym == 'Return':
       continue
    else:
        exit

    print
    print

然后我想，也许我已经用字符串变量“ answer”替换了“ event”，但随后出现此错误：

Traceback (most recent call last):
  File "/home/q/Desktop/PigsAndBulls.py", line 52, in <module>
    if answer.keysym == 'Return':
AttributeError: 'str' object has no attribute 'keysym'

另外，如果我按其他任何键，它只会在空闲状态下打印，并且程序不会退出。

顺便说一句，我知道必须有一种使用列表或词典对此进行编程的更好方法，但这就是我所知道的全部方法。