python - Python变量行中的for循环问题未定义

Question

我正在使用 mysql-connector-python 创建一个大型程序，但在使用 if-else 后，它陷入了一个错误:变量行未定义 for 循环 中的语句。

这是我遇到错误的代码部分:

elif question == 'login' or 'login'.upper():
        email1 = input("Your email: ")
        passw1 = input("Your password: ")
        if '@' and '.' or '.com' in email:
            if len(passw1) > 5:
                mycursor.execute("USE register;")
                mycursor.execute("SELECT * FROM id;")
       # ------------------------------------------------#
                for row, col in mycursor.fetchall():    #|
                    pass                                #|    Here is the line which is affecting my code
                if email1 in row:                       #|   
                    if passw1 in col:                   #|
       # ------------------------------------------------#
                        print("Successfuly signed in!!")
                        break

这是完整的代码:

import mysql.connector

mydb = mysql.connector.connect(
    host="localhost",
    user="root",
    passwd="",
    database="register"
)

mycursor = mydb.cursor()
# OTP
OTP = 1234
# asking to choose
question = input("Would you like to login or signup?? ")
# sign up
while True:
    if question == 'signup':
        email = input("--------------------------\nYour email: ")
        passw = input("Your password: ")
        confirm_pass = input("Confirm password: ")
        mycursor.execute("USE register;")
        mycursor.execute("SELECT * FROM id;")
        for row, col in mycursor.fetchall():
            pass
        if email in row:
            if passw in col:
                print("Already logged in!!")
        elif '@' and '.' or '.com' in email:
            if passw == confirm_pass:
                if len(passw) > 5:
                    print("----------------------------\nSuccessfuly registered!")
                    mycursor.execute("USE register;")
                    query = "INSERT INTO id(email, passw) VALUES(%s,%s);"
                    args = (email, passw)
                    mycursor.execute(query, args)
                    mydb.commit()
                    break
                else:
                    print("Your password is too short")

            else:
                print("Passwords didn't match!")

        else:
            print("wrong email")

     # login condition
    elif question == 'login' or 'login'.upper():
        email1 = input("Your email: ")
        passw1 = input("Your password: ")
        if '@' and '.' or '.com' in email:
            if len(passw1) > 5:
                mycursor.execute("USE register;")
                mycursor.execute("SELECT * FROM id;")
                for row, col in mycursor.fetchall():
                    pass
                if email1 in row:
                    if passw1 in col:
                        print("Successfuly signed in!!")
                        break
                    else:
                        print("wrong email or password!!")
                        forgot_pass = input("Forgot password? \nYes/no ")
                        if forgot_pass == 'yes':
                            print("Yes")
                        elif forgot_pass == 'no':
                            print("No")
                        else:
                            print("Blah blah blah")
                else:
                    print("wrong email or password!!")
                    forgot_pass = input("Forgot password? \nYes/no ")
                    if forgot_pass == 'yes':
                        print("We have send an OTP at your email")
                        enter_OTP = int(input("Type OTP within 1 minute "))
                        if enter_OTP == OTP:
                            change_passw = input("Type new password ")
                        else:
                            print("Wrong OTP!")
                            break
                    elif forgot_pass == 'no':
                        print("No")
                    else:
                        print("Blah blah blah")
            else:
                print("Your password is too short")
        else:
            print("wrong email")
    else:
        print("Blah blah blah...")

Answer 1

您在 for 循环范围之外引用了变量 row。

for row, col in mycursor.fetchall():
    # notice that row and passw1 are now indented inside the for loop block
    if email1 == row and passw1 == col:
        print("Successfuly signed in!!")
        break

参见python-scopes-and-namespaces了解更多详情。