Python:If语句、原始输入和列表生成器

Question

我在接受用户输入时遇到了一个奇怪的问题，在列表中添加了正确的信息，并检查列表中是否有正确的输入

出于某种原因，只输入'pally'调用end_instance.enter()（不带'polly'）

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中布尔上下文中的{}。使用or和and计算 带短路计算的布尔表达式：

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

因此，该行：

if 'polly' and 'pally' in green_ans:

相当于说：

if 'pally' in green_ans:

因此，只有'pally'起作用

Answer 2

'polly'将始终为真

因此，请将代码更改为：

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