因为文件已经存在，所以要求用户创建新的用户名

Question

基于程序。它可以根据用户输入的用户名保存文件。由于用户名已经存在，如何让程序要求用户更改为其他用户名。

while True:
RegOrLog = raw_input('[Register/Login]:')
if RegOrLog not in ('reg', 'register', 'REGISTER','log', 'login', 'LOGIN',\
                    'r','l'):
    print "Please enter 'register' if you dont have account"
    print "Please enter 'login' if you already registered"

if RegOrLog in ('reg', 'register', 'REGISTER','r','Register'):
    count = 0
    while count < 1:
        regusrnm = raw_input('Enter your desire login name:')
        regusrnm = regusrnm.lower()
        regpswrd = raw_input('Enter your password:')
        while True:
            regage = raw_input('Enter your age:')
            if int(regage) not in range(1, 100):
                print 'please enter apropriate value'
            else:
                break

        while True:
            reggender = raw_input('State your gender:')
            if reggender not in ('male', 'female'):
                print 'Are you an alien?'
            else:
                break

        data = {"username": regusrnm, "password": regpswrd, "age": regage,\
                "gender": reggender}
        pickle.dump( data, open( regusrnm, "wb" ) )
        RegOrLog = 'login'
        print 'Please login to your account for security purpose'
        break

if RegOrLog in ('log', 'login', 'LOGIN','l','Login'):
    logusrnm = raw_input('Enter your username:')
    data = pickle.load( open( logusrnm, "rb" ) )
    count = 3
    while count >= 1:
        logpswrd = raw_input('Enter your password:')
        count = count - 1
        if logpswrd != data["password"]:
            print "You have",count, "attempt left"
            if count == 0:
                print "The account doesn't exist or wrong password"
                print 'Please register a new one'
                break

        else:
            print 'Welcome Back',data["username"]
            break

以及如何将保存文件存储在文件夹中，以免弄得乱七八糟。喜欢干净整洁:D

Answer 1

import os.path
os.path.exists(file_name)

Returns True 如果名称为 file_name 的目录或文件存在。所以你只需检查

if os.path.exists(regusrnm) == True:
    # ask user to enter another name

这意味着你改变了

if RegOrLog in ('reg', 'register', 'REGISTER','r','Register'):
    count = 0
    while count < 1:

到

if RegOrLog in ('reg', 'register', 'REGISTER','r','Register'):
    count = 0
    while os.path.exists(regusrnm) == True:

在此之前，您需要为 regusrnm 分配一些值。 admin 似乎是一个不错的选择，因为每个系统都有一个 admin :)

所以整个部分是

regusrnm = 'admin'
if RegOrLog in ('reg', 'register', 'REGISTER','r','Register'):
    count = 0
    while os.path.exists(regusrnm) == True:

您还可以使用 os.path.isfile(file_name) 来检查 file_name 是否是文件（而不是目录）。

因为文件已经存在，所以要求用户创建新的用户名

ask the user to make new username since the file already existed

python-2.7

save

file-exists