Question

我有一个奇怪的问题是接受用户输入，附加一个包含正确信息的列表，并检查列表是否输入正确。

出于某种原因，只有进入＆＃39; pally＆＃39;致电end_instance.enter()（没有＆＃39; polly＆＃39;）。

def enter(self):
    print """Please enter your two passwords to proceed. Check the other doors for answers. You have five guesses."""

    green_count = 0

    green_ans = []

    while green_count < 5:

        green_guess = (raw_input('> '))

        if 'polly' or 'pally' in green_guess:
            green_ans.append(green_guess)
            green_count += 1

            if 'polly' and 'pally' in green_ans:
                print "cool"
                end_instance.enter()
        else:
            print "try again"
            green_count += 1

Answer 1

'polly'和'pally'都是非空字符串，因此等同于 Python中的布尔上下文中的True。使用or和and计算具有短路评估的布尔表达式：

>>> 'polly' or 'pally'
'polly'   # first True value; second not checked
>>> 'polly' and 'pally'
'pally'   # last True value; both checked

所以，行：

if 'polly' and 'pally' in green_ans:

相当于说：

if 'pally' in green_ans:

因此，只有'pally'有效。

Answer 2

'polly'永远都是真的。

因此，请将您的代码更改为：

def enter(self):
    print """Please enter your two passwords to proceed. Check the other doors for answers. You have five guesses."""

    green_count = 0

    green_ans = []

    while green_count  '))

        if 'polly' in green_guess or 'pally' in green_guess:
            green_ans.append(green_guess)
            green_count += 1

            if 'polly' in green_guess and 'pally' in green_guess:
                print "cool"
                end_instance.enter()
        else:
            print "try again"
            green_count += 1

Python：如果语句，Raw_Input和List Gen

2 个答案: