Question

因此，正如标题所示，我正在尝试做一个待办事项列表CLI应用程序，并且遇到了该错误。（NameError: name 'loaded_uinput' is not defined）

当我将load_uinput设置为全局变量时，它会给我该错误，但是如果我不这样做，则会给我一个错误：UnboundLocalError: local variable 'loaded_uinput' referenced before assignment

我一直在努力研究整天，以寻找我做错了什么，但是除了写得不好的代码（目前，我打算很快将其重构）之外，我找不到它：/


userlist = []
filename = "userdata.p"

def maininput():
    while True:
        #Selecting if user wants to read or write the list, and or exit
        init_conf = input("Would you like to read or write your list? (read | write | exit)")
        #Printing the list
        if init_conf == "read":
            pickle_in = open(filename, "rb")
            loaded_uinput = pickle.load(pickle_in, encoding='bytes')
            pickle_in.close()
            print(*loaded_uinput, sep="\n")
        #Customizing the list
        elif init_conf == "write":
            uinput = input("What would you like to add to your list?")
            userlist.append("-" + uinput)
            pickle_out = open(filename, "ab")
            pickle.dump(userlist, pickle_out)
            pickle_out.close()
            print(*loaded_uinput, sep="\n")
        elif init_conf == "exit":
            break

maininput()

我只想让它运行时没有错误哈哈，甚至不理解它是如何定义的：我想写一些东西并将其存储在userdata.p

中

谢谢！

Answer 1

您只需要在循环之前定义变量。它仅在“ if”块范围内创建，而不是在尝试访问它的“ elif”块时创建。您可以根据需要将其设置为空列表。

userlist = []
filename = "userdata.p"

def maininput():
    loaded_uinput = []
    while True:
        #Selecting if user wants to read or write the list, and or exit
        init_conf = input("Would you like to read or write your list? (read | write | exit)")
        #Printing the list
        if init_conf == "read":
            pickle_in = open(filename, "rb")
            loaded_uinput = pickle.load(pickle_in, encoding='bytes')
            pickle_in.close()
            print(*loaded_uinput, sep="\n")
        #Customizing the list
        elif init_conf == "write":
            uinput = input("What would you like to add to your list?")
            userlist.append("-" + uinput)
            pickle_out = open(filename, "ab")
            pickle.dump(userlist, pickle_out)
            pickle_out.close()
            print(*loaded_uinput, sep="\n")
        elif init_conf == "exit":
            break

maininput()

Answer 2

请勿将loaded_uinput定义为函数外部的全局变量。如果在定义之前尝试使用UnboundLocalError，则会出现loaded_uinput，如果在while循环的第一个迭代中init_conf == "write"是True时可能会发生。也就是说，如果您第一次键入"write"，则在尝试将其用于打印输出时将不会定义loaded_uinput。

Answer 3

发生错误是因为您在尝试向loaded_uinput变量分配任何值之前对其进行了访问。

当循环首次运行并输入'write'命令时，循环获取将输入的数据获取到uinput并将其保存到文件，但尝试打印print(*loaded_uinput, sep="\n")而不是尚未分配。它应该更改为：

print(*uinput)

open(filename, "ab")已更改为替换文件的内容，而不是附加到文件。

open(filename, "wb")

检查此工作代码：

import pickle
userlist = []
filename = "userdata.p"

def maininput():
    while True:
        #Selecting if user wants to read or write the list, and or exit
        init_conf = input("Would you like to read or write your list? (read | write | exit)")
        #Printing the list
        if init_conf == "read":
            pickle_in = open(filename, "rb")
            loaded_uinput = pickle.load(pickle_in)
            pickle_in.close()
            print(*loaded_uinput, sep="\n")
        #Customizing the list
        elif init_conf == "write":
            uinput = input("What would you like to add to your list?")
            userlist.append("-" + uinput)
            pickle_out = open(filename, "wb")
            pickle.dump(userlist, pickle_out)
            pickle_out.close()
            print(*uinput)
        elif init_conf == "exit":
            break

maininput()

此处的工作示例：https://repl.it/repls/VapidDescriptiveMiddleware

NameError：名称“”未定义，试图创建待办事项列表CLI应用程序

3 个答案: