Question

在我的学校项目中，我必须创建全局“客户列表”功能，所以我不必每次在其他功能中需要此文件时打开我的文件。这里说没有定义client_list：

global client_list

def clients():
    client_list = []
    with open("svi.txt","r") as f:
        every_part = ["username","password","name","lastname","role"]
        for r in f.readlines():
            dicct = {}
            bla = r.strip().split("|")
            count = 0
            for i in bla:
                dicct[every_part[count]] = i
                count += 1
            client_list.append(dicct)
def log(file_path,user,password,delimiter):
    for r in client_list:
        n = r.strip().split(delimiter)
        username = n[0]
        passwordd = n[1]
        role = n[4]
        while username == user and passwordd == password:
            if role == "buyer":
                return buyer_menu2()
            elif role == "manager":
                return menager_menu2()
            elif role == "seller":
                return seller_menu2() 
    return False
def login():
    x = False

    while x == False:
        user = input("Username: ")
        password = input("Password: ")
        x = log("svi.txt",user,password,"|")
        if x == False:
            print()
            print("Wrong username or password, please try again. ")
            print()
    print()
login()

Answer 1

如上所述here，Python中的global关键字用于在本地上下文中突变或定义全局变量。您不需要它在已经全局范围内声明全局变量，因此在您编写global client_list的位置时，您可以通过编写类似client_list = []

的内容来定义变量本身

需要global关键字在您打算修改全局client_list变量的任何函数中。因此，例如，如果您打算将clients()函数附加到（或以其他方式改变）全局client_list，则它应包含global client_list声明。

def clients():
    global client_list
    with open("svi.txt","r") as f:
    <the rest of your function>

Answer 2

如果通过＆＃34;全局函数＆＃34;，您实际上是指＆＃34;全局变量＆＃34;，以下内容应该有所帮助：

client_list = []

def clients():
    global client_list
    client_list = []
    with open("svi.txt","r") as f:
        every_part = ["username","password","name","lastname","role"]
        for r in f.readlines():
            dicct = {}
            bla = r.strip().split("|")
            count = 0
            for i in bla:
                dicct[every_part[count]] = i
                count += 1
            client_list.append(dicct)
def log(file_path,user,password,delimiter):
    # No need to declare client_list as global for reading it
    for r in client_list:
        n = r.strip().split(delimiter)
        username = n[0]
        passwordd = n[1]
        role = n[4]
        while username == user and passwordd == password:
            if role == "buyer":
                return buyer_menu2()
            elif role == "manager":
                return menager_menu2()
            elif role == "seller":
                return seller_menu2() 
    return False
def login():
    x = False

    while x == False:
        user = input("Username: ")
        password = input("Password: ")
        x = log("svi.txt",user,password,"|")
        if x == False:
            print()
            print("Wrong username or password, please try again. ")
            print()
    print()
login()

所以不要将client_list声明为文件顶部的全局，而是要在那些要更改其内容的函数中声明。

根据评论进行修改： 当然，您必须在程序中至少调用一次clients才能最初填写您的client_list。这不是我的代码，因为我只是拿走了你的代码，并假设你已经在其他地方做过了。

newbie python - 将全局函数转换为其他函数

2 个答案: