Question

很抱歉，如果我说错了或格式错了，这是我第一次来这里。基本上，这个脚本是一个非常非常简单的文本编辑器。问题是，当它写入文件时，我希望它写：

Hi, my name
is bob.

但是，它写道：

is bob.
Hi, my name

我该如何解决这个问题？代码在这里：

import time
import os
userdir = os.path.expanduser("~\\Desktop")
usrtxtdir = os.path.expanduser("~\\Desktop\\PythonEdit Output.txt")
def editor():
    words = input("\n")
    f = open(usrtxtdir,"a")
    f.write(words + '\n')
    nlq = input('Line saved. "/n" for new line. "/quit" to quit.\n$ ')
    if(nlq == '/quit'):
        print('Quitting. Your file was saved on your desktop.')
        time.sleep(2)
        return
    elif(nlq == '/n'):
        editor()
    else:
        print("Invalid command.\nBecause Brendan didn't expect for this to happen,\nthe program will quit in six seconds.\nSorry.")
        time.sleep(6)
        return
def lowlevelinput():
    cmd = input("\n$ ")
    if(cmd == "/edit"):
        editor()
    elif(cmd == "/citenote"):
        print("Well, also some help from internet tutorials.\nBut Brendan did all the scripting!")
        lowlevelinput()
print("Welcome to the PythonEdit Basic Text Editor!\nDeveloped completley by Brendan*!")
print("Type \"/citenote\" to read the citenote on the word Brendan.\nType \"/edit\" to begin editing.")
lowlevelinput()

Answer 1

很好的谜题。为什么这些线路反向出现？由于输出缓冲：

写入文件时，系统不会立即将数据提交到磁盘。这种情况会定期发生（当缓冲区已满时），或文件关闭时。您永远不会关闭f，因此当f超出范围时它会关闭...当函数editor()返回时会发生这种情况。但 editor()递归调用自己！因此，对editor()的第一次调用是最后一次退出，其输出是最后一次提交到磁盘。干净，嗯？

要解决问题，只要写完就关闭f就足够了：

f = open(usrtxtdir,"a")
f.write(words + '\n')
f.close()   # don't forget the parentheses

或同等的：

with open(usrtxtdir, "a") as f:
    f.write(words + '\n')

但最好修复程序的组织：

使用循环运行editor()，而不是递归调用。
编辑器应该在会话结束时写出文件，而不是每行输入。考虑在行列表中收集用户输入，并在最后一次写出所有内容。
如果你想要随时写，你应该只打开文件一次，反复写，然后在完成后关闭它。

Answer 2

您需要在写入之后关闭文件，然后再尝试再次打开它。否则，在程序关闭之前，您的写入将不会完成。

def editor():
    words = input("\n")
    f = open(usrtxtdir,"a")
    f.write(words + '\n')
    nlq = input('Line saved. "/n" for new line. "/quit" to quit.\n$ ')
    f.close()  # your missing line!
    if(nlq == '/quit'):
        print('Quitting. Your file was saved on your desktop.')
        time.sleep(2)
        return
    elif(nlq == '/n'):
        editor()
    else:
        print("Invalid command.\nBecause Brendan didn't expect for this to happen,\nthe program will quit in six seconds.\nSorry.")
        time.sleep(6)
        return

Answer 3

如果替换：

f = open(usrtxtdir,"a")
f.write(words + '\n')

使用：

with open(usrtxtdir,"a") as f:
    f.write(words + '\n')

它按顺序出现。几乎总是使用with open()进行文件访问。即使在崩溃的情况下，它也会自动为您处理文件的关闭。虽然您可能会考虑在内存中处理文本并仅在退出时编写它。但这并不是手头问题的一部分。

Answer 4

Python的file.write()文档指出：“由于缓冲，在调用flush()或close()方法之前，字符串实际上可能不会显示在文件中”

由于你在递归文件并在关闭它之前写入文件（或刷新缓冲区），因此在内部框架（你写的'时）尚未写入外部值（'嗨，我的名字'）是bob。'）完成，它似乎自动刷新写缓冲区。

你应该能够添加file.flush（）来纠正它：

import time
import os
userdir = os.path.expanduser("~\\Desktop")
usrtxtdir = os.path.expanduser("~\\Desktop\\PythonEdit Output.txt")
def editor():
    words = input("\n")
    f = open(usrtxtdir,"a")
    f.write(words + '\n')
    f.flush() # <-----   ADD THIS LINE HERE   -----< #
    nlq = input('Line saved. "/n" for new line. "/quit" to quit.\n$ ')
    if(nlq == '/quit'):
        print('Quitting. Your file was saved on your desktop.')
        time.sleep(2)
        return
    elif(nlq == '/n'):
        editor()
    else:
        print("Invalid command.\nBecause Brendan didn't expect for this to happen,\nthe program will quit in six seconds.\nSorry.")
        time.sleep(6)
        return
def lowlevelinput():
    cmd = input("\n$ ")
    if(cmd == "/edit"):
        editor()
    elif(cmd == "/citenote"):
        print("Well, also some help from internet tutorials.\nBut Brendan did all the scripting!")
        lowlevelinput()
print("Welcome to the PythonEdit Basic Text Editor!\nDeveloped completley by Brendan*!")
print("Type \"/citenote\" to read the citenote on the word Brendan.\nType \"/edit\" to begin editing.")
lowlevelinput()

另外，完成后请不要忘记关闭文件！

脚本反向写入

4 个答案: