Question

我试图做一个基本的登录系统，但我有一些逻辑问题。

我想在没有填写电子邮件或密码字段时显示“登录不正确”消息，并且当结果不包含通知电子邮件和密码的用户时也是如此。

但是当电子邮件或密码字段未填写时，它没有显示“登录不正确”消息

你可以帮忙让这个工作正常吗？

def login():

    while True:
        email = ""
        password = ""
        while not email or not password:
            email = raw_input("Enter your username:")
            password = raw_input('Password:')
        results = # get a row from database where email = email and password = password
        for result in results:
            if result["email"] == email and result["password"] == password:
                print "Login correct"               
                return True
            else:
                return False

def main():
    if login():
        # do something
    else:
        print "Login is incorrect"

main()

Answer 1

def login():

    while True:
        email = ""
        password = ""
        while not email or not password:
            email = raw_input("Enter your username:")
            password = raw_input('Password:')
        results = # get a row from database where email = email and password = password
        for result in results:
            if result["email"] == email and result["password"] == password:
                print "Login correct"               
                return True
            else:
                print "Login incorrect" 
                return False

Answer 2

问题在于登录方式：

def login():

while True:
    email = ""
    password = ""
    while not email or not password:
        email = raw_input("Enter your username:")
        password = raw_input('Password:')
        if not email or not password:
           return False #this is the key

    results = # get a row from database where email = email and password = password
    for result in results:
        if result["email"] == email and result["password"] == password:
            print "Login correct"               
            return True
        else:
            return False

def main():
    if login():
        # do something
    else:
        print "Login is incorrect"

main()

Answer 3

您的代码中存在逻辑错误。

您要求您的数据库为您提供具有匹配用户和密码的所有结果。结果应该是完全一行或没有行。

如果你有一行，那一定是正确的。无需再次比较用户名和密码，因为您在数据库查询中执行了此操作。

如果数据库查询产生没有行，您的代码将不会进入for循环，因此不会打印任何内容。

如果未填写电子邮件或密码字段，则不显示“登录不正确”消息

3 个答案: