Question

我试图在这段短代码中弄清楚问题。任何帮助，将不胜感激。无论我指定User.email是什么，它总是返回false。

def add(self):

    #1 -- VALIDATE EMAIL ADDRESS
    #Check that e-mail has been completed
    try:
        #Validate if e-mail address is in correct format
        if (isAddressValid(self.email) == 0):
            self.errors['email'] = 'You have entered an invalid e-mail address';
            return 0

    except NameError:
        self.errors['email'] = 'Please enter your e-mail'
        return 0

>>> u = User()
>>> u.email = 'test@example.com'
>>> u.add()
0
>>> print u.errors
{'email': 'Please enter your e-mail'}

我已经确认返回的错误来自NameError。

另外，isAddressValid（）只是一种检查电子邮件地址结构的方法。

感谢。

Answer 1

您尚未为正面案例添加return语句...此外，当函数不包含return语句时，调用方会收到None而不是def add(self): #1 -- VALIDATE EMAIL ADDRESS #Check that e-mail has been completed try: #Validate if e-mail address is in correct format if (isAddressValid(self.email) == 0): self.errors['email'] = 'You have entered an invalid e-mail address'; return False except NameError: self.errors['email'] = 'Please enter your e-mail' return False return True。。

{{1}}

Answer 2

实际上你有两个值。

0
None

如果您打印值而不是在if语句中使用它，您将看到两个条件。考虑添加print语句以查看实际值是什么。

if (isAddressValid(self.email) == 0):

如果这是True，则会得到0。

如果这是假的，您将获得None。

例外情况为0。

Answer 3

如果我重写这段代码，我会选择这样的东西：

def add(self):
    try:
        if not isAddressValid(self.email):
            self.errors['email'] = 'You have entered an invalid e-mail address';
    except NameError:
        self.errors['email'] = 'Please enter your e-mail'
    return 'email' not in self.errors

Answer 4

我不确定你在说什么问题，但你总是回来0

尝试为有效电子邮件（您目前没有考虑）的情况添加else子句

def add(self):

#1 -- VALIDATE EMAIL ADDRESS
#Check that e-mail has been completed
try:
    #Validate if e-mail address is in correct format
    if (isAddressValid(self.email) == 0):
        self.errors['email'] = 'You have entered an invalid e-mail address';
        return 0
    else
        return 1

except NameError:
    self.errors['email'] = 'Please enter your e-mail'
    return 0

Answer 5

你说isAddressValid是一种方法，对吧？由于add也是一种方法，因此您可能需要预先添加self.：

if (self.isAddressValid(self.email) == 0):

这很可能会处理您的NameError。

之后，在检查成功时添加else子句：

    …
    self.errors['email'] = 'You have entered an invalid e-mail address'
    return 0
else:
    return 1

Python try / except ...函数总是返回false

5 个答案: