如何循環輸入密碼/用戶名登錄頁面並從外部文件讀取密碼/用戶名？

Question

我知道有關如何循環和讀取文本文件的多個帖子和資源。 我很抱歉成為那個人，但是我是Python的新手，我打算在凌晨1:00編寫這篇文章。

如標題所示，如何循環登錄頁面，以便如果用戶輸入錯誤的詳細信息，那么他們將有另一種嘗試機會，直到他們正確輸入了詳細信息。 密碼/用戶名也需要從外部文件中讀取。

我的代碼：

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

做這樣的事情：

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")

您可以使用file = open("externalfile.txt","r")從外部文件讀取內容，然后執行text = file.read() ，如果文件的格式為

username
password

做text = text.split("\\n")然后username = text[0]和password = text[1]

這是它的樣子，並帶有一個解釋：

file = open("password.txt","r") #this opens the file and saves it to the variable file
text = file.read() #this reads what is in the file and saves it to the variable text
text = text.split("\n") #this makes the text into a list by splitting it at every enter
username = text[0] #this sets the username variable to the first item in the list (the first line in the file). Note that python starts counting at 0
password = text[1] #this sets the password variable to the second item in the list (the second line in the file)
theirUsername = input("What is your username") #gets username input
theirPassword = input("What is your password") #get password input
while theirUsername != username or theirPassword != password: #repeats the code inside while theirUsername is not equeal to username or theirPassword is not equal to password
    print("incorrect") #notifies them of being wrong
    theirUsername = input("What is your username") #gets new username input
    theirPassword = input("What is your password") #gets new password input
print("correct") #tells them they are corrected after the looping is done and the password and username are correct

Answer 2

因此，您想循環播放。 一個好的地方在哪里？ 當我們問一個問題時怎么樣。

現在，看看獲得正確的用戶名和密碼的情況。 我們不想在循環中處理它。 僅在此循環中獲取正確的用戶名和密碼。

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")

現在從文件中讀取您的用戶名/密碼。 讓我們簡單點。 第一行是用戶名，第二行是密碼。 沒有其他項目。

現在創建一個適當的功能。

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

現在修復您的代碼以使用該功能。

username, password = read_credentials_from_file(...)

請注意，在函數中我們去除了行尾。 如果使用的是Python 3.7，請使用breakpoint函數單步執行代碼並觀察其作用。

Answer 3

假設您的文本文件（credentials.txt）讀為：

Janupedia
12345

也許這樣的事情將為您工作。 我評論了我添加的代碼。 您可能想要將憑證文件命名為其他名稱。

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")