Question

我知道有关如何循环和读取文本文件的多个帖子和资源。我很抱歉成为那个人，但是我是Python的新手，我打算在凌晨1:00编写这篇文章。

正如标题所示，如何循环登录页面，以便如果用户输入错误的详细信息，那么他们将有另一种尝试机会，直到他们正确输入了详细信息。密码/用户名也需要从外部文件中读取。

我的代码：

print ("\nEnter details to access wallet...\n")
username = 'Janupedia'
password = '12345'
userInput = input("What is your username?\n")
if userInput == username:
    userInput = input("Password?\n")   
    if userInput == password:
       print("Welcome!")
       print('\n--------------------------------------------------------\n')
       print ("BTN = 0.10")
       print ("= £315.37")
    else:
       print("That is the wrong password.")
else:
    print("That is the wrong username.")
print('\n--------------------------------------------------------\n')

Answer 1

做这样的事情：

data <-
structure(list(QuestionNumber = structure(c(17L, 17L, 17L, 17L, 
17L, 17L, 17L, 17L, 16L, 16L, 16L, 16L, 16L, 16L, 16L, 15L, 15L, 
15L, 15L, 15L), .Label = c("Q17", "Q16", "Q15", "Q14", "Q13", 
"Q12", "Q11", "Q10", "Q9", "Q8", "Q7", "Q6", "Q5", "Q4", "Q3", 
"Q2", "Q1"), class = c("ordered", "factor")), stemmed = structure(c(2L, 
1L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 1L, 1L, 1L, 1L, 3L, 1L, 2L, 2L, 
3L, 2L, 3L), .Label = c("No", "Yes", "Maybe"), class = "factor")), row.names = c(NA, 
20L), class = "data.frame")

您可以使用password = "password" username = "username" theirUsername = input("What is your username") theirPassword = input("What is your password") while theirUsername != username or theirPassword != password: print("incorrect") theirUsername = input("What is your username") theirPassword = input("What is your password") print("correct")从外部文件中读取内容，然后执行file = open("externalfile.txt","r")并确定文件的格式为

text = file.read()

先执行username password，然后执行text = text.split("\n")和username = text[0]

这应该是带有解释的样子：

password = text[1]

Answer 2

因此您想循环播放。一个好的地方在哪里？我们问一个问题怎么样？

现在，看看获得正确的用户名和密码的情况。我们不想在循环中处理它。只有在循环中才能获取正确的用户名和密码。

print("\nEnter details to access wallet...\n")
username = "Janupedia"
password = "12345"
userInput = ""
while userInput != password:
    userInput = input("What is your username?\n")
    if userInput == username:
        userInput = input("Password?\n")
        if userInput == password:
            break
        else:
            print("That is the wrong password.")
    else:
        print("That is the wrong username.")

print("Welcome!")
print("\n--------------------------------------------------------\n")
print("BTN = 0.10")
print("= £315.37")
todo_list = open("Credentials", "a")
todo_list.write("Username = Janupedia + Password = 12345")
todo_list.close()
print("\n--------------------------------------------------------\n")

现在从文件中读取您的用户名/密码。让我们简单点。第一行是用户名，第二行是密码。没有其他项目。

现在创建适当的功能。

def read_credentials_from_file(filename):
    """Read the file and return (username, password).
    File contents are first line username and second line password.
    """
    # Using the `with` statement is current best practice.
    with open(filepath, "rt") as user:
        username = user.readline().strip()
        password = user.readline().strip()
    return username, password

现在修复您的代码以使用该功能。

username, password = read_credentials_from_file(...)

请注意，在函数中，我们去除了行尾。如果您使用的是Python 3.7，请使用breakpoint函数单步执行代码并观察其作用。

Answer 3

假设您的文本文件（credentials.txt）读为：

Janupedia
12345

也许类似的东西对您有用。我评论了我添加的代码。您可能想要将凭证文件命名为其他名称。

print ("\nEnter details to access wallet...\n")
"""
Open File
"""
with open("Credentials.txt", "r") as f:
    array = []
    for line in f:
        array.append(line) #stores username and password
username = array[0]
password = array[1]
login = 0 #initial login status
while login == 0: #as long as login status = 0 loop repeats
    userInput = input("Username?")
    if username.strip(' \n') == userInput.strip(' \n'):
        userInput = input("Password?")  
        if password.strip(' \n') == userInput.strip(' \n'):
            login = 1 #login successful set login status to 1 thus breaking loop 
        else:
            print("Incorrect")
    else:
        print("Incorrect")
        print('\n--------------------------------------------------------\n')
#  Login successful loop finished
print("Welcome!")
print('\n--------------------------------------------------------\n')
print ("BTN = 0.10")
print ("= 315.37")

如何循环输入密码/用户名登录页面并从外部文件读取密码/用户名？

3 个答案: