如何访问存储在变量名下的文本文件

Question

尝试从 Python 访问外部文本文件时，我在尝试简单地查看文件内容和尝试添加到文件时遇到了几个问题。所涉及的程序部分采用用户名并在该用户名下创建一个文本文件（如果尚不存在）。使用Create()函数时，遇到如下TypeError:

Exception in Tkinter callback
Traceback (most recent call last):
  File "D:\Python 3.3.2\A Level Computer Science\Whosebugsolution.py", line 48, in View
    with open(userfile, 'r') as u:
FileNotFoundError: [Errno 2] No such file or directory: 'name.txt'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "D:\Python 3.3.2\Python files\lib\tkinter\__init__.py", line 1475, in __call__
    return self.func(*args)
  File "D:\Python 3.3.2\A Level Computer Science\Whosebugsolution.py", line 91, in Add
    u.write(addText.get())
TypeError: get() missing 1 required positional argument: 'index1'

这是遇到错误的代码：

from tkinter import *
import os

def Login():

    global nameEL
    global rootA

    rootA = Tk()
    rootA.title('Login')

    intruction = Label(rootA, text='Please Login\n')
    intruction.grid(sticky=E)

    nameL = Label(rootA, text='Username: ')
    nameL.grid(row=1, sticky=W)

    nameEL = Entry(rootA)
    nameEL.grid(row=1, column=1)

    loginB = Button(rootA, text='Login', command=LoggedIn)
    loginB.grid(columnspan=2, sticky=W)
    rootA.mainloop()

def LoggedIn():

    global userfile

    roots1 = Tk()
    roots1.title('Logged in successfully')
    roots1.geometry('300x300')

    userfile = nameEL.get() + '.txt'

    View1 = Button(roots1, text='View', command=View)
    View1.grid(columnspan=10, sticky=W)
    View1.pack(fill = 'x')

    Create1 = Button(roots1, text='Create', command=Create)
    Create1.grid(columnspan=10, sticky=W)
    Create1.pack(fill = 'x')

def View():

    global userfile

    try:
        with open(userfile, 'r') as u:
            print(u.read())
    except FileNotFoundError:
        r = Tk()
        r.title('View')
        r.geometry('300x50')
        rlbl = Label(r, text='\n[!] Theres nothing to see here [!]')
        rlbl.pack()
        r.mainloop()
        LoggedIn()
    except ValueError:
        r = Tk()
        r.title('View')
        r.geometry('300x50')
        rlbl.pack()
        r.mainloop()
        LoggedIn()

def Create():

    global addText
    global rootC

    rootC = Tk()
    rootC.title('Lets add some information')
    instruction = Label(rootC, text='Please enter the information you would like to add\n')
    instruction.grid(row=0, column=0, sticky=W)

    newText = Label(rootC, text='info: ')
    newText.grid(row=1, column=0)

    addText = Text(rootC)
    addText.grid(row=2, column=0)

    addButton = Button(rootC, text='Add', command=Add)
    addButton.grid(columnspan=2, sticky=W)
    addButton.grid(row=3, column=0)

def Add():

    global userfile

    with open(userfile, 'a') as u:
        u.write(addText.get())
        u.write('\n')

        rootC.destroy()
        LoggedIn()

Login()

Answer 1

我会这样做：

def LoggedIn():

    global userfile

    roots1 = Tk()
    roots1.title('Logged in successfully')
    roots1.geometry('300x300')

    userfile = nameEL.get() + '.txt'
    #and the tkinter widgets

此代码 userfile = open(nameEL.get() + '.txt', 'a') 有点奇怪，您正在使用 open 命令创建一个对象，稍后您将其用作字符串。你只需要 userfile 是一个字符串，而不是一个命令。然后，您可以使用它打开文件（见下文）

def View():

    global userfile

    try:
        with open (userfile, 'r') as u:
            print (u.read())
    except FileNotFoundError: #file doesn't exist
        r = Tk()
        r.title('View')
        r.geometry('300x50')
        rlbl = Label(r, text='\n[!] This file doesn't exist [!]')
        rlbl.pack()
        r.mainloop()
        LoggedIn()
    except ValueError: #some error when reading
        r = Tk()
        r.title('View')
        r.geometry('300x50')
        rlbl = Label(r, text='\n[!] Problem when reading the file [!]')
        rlbl.pack()
        r.mainloop()
        LoggedIn()

在这里，print(userfile.read()) 无法正常工作，因为您使用 append 模式创建了userfile（也许还有其他问题）

最后

def Add():
    global userfile

    with open(userfile, 'a') as u:
        u.write(addText.get()) #don't forger the .get ()
        u.write('\n')

    rootC.destroy()
    LoggedIn()

在这里，您试图在文件中写入一个 Entry 对象，Python 不喜欢这样。您只需要添加 .get() 以便它写入 Entry 对象 addText 中的内容。这里还有一个错误：当使用 with () 命令时，您不需要关闭文件，它会自动完成。可能仍然存在问题，但文件应该可以正常工作。

编辑：使用 Text 小部件时，get() 命令比仅使用 Entry 小部件时需要更多参数你可以使用这个：

u.write (addText.get('1.0', END))

如何访问存储在变量名下的文本文件

How to access a text file stored under a variable name

python

python-3.x

tkinter

python-3.3