Python：文本文件中特定单词后的换行符

我有一个文本文件，只有一行10.000字。 现在，我想在出现特定单词（“注释”）之前添加一个换行符，并将其写入新的文本文件：

文本文件看起来像：“注释：是的，你说得对注释：那很有趣注释：真的吗

新文件应该如下所示：

    Comment: Yeah, you're right
    Comment: That's very interesting
    Comment: really?

我尝试了下面的代码，但出现了一些问题。我是一个初学者，直到现在，我还没有找到解决方案。谢谢你的帮助

    -*- coding: utf-8 -*-

    d = file('test.txt','r')
    text=d.read()
    e = file('output.txt','w')
    x=raw_input("Insert word:")
    # -> Comment
    for line in d.readlines():
          if line.startswith(x):
            word.append(+"\n")
            e.write()
            e.close()
            d.close()

---

您只需要使用str.replace：

e.write(d.read().replace(' Comment:', '\nComment:'))

---

一个非常简单的解决方案可以是：

for line in d.readlines():
    e.write(line.replace("Comment:",  "\nComment:"))

e.close()    

---

您可以执行

'\n'。将（x+'：'+字符串连接到第行的字符串中。拆分（x+'：'）

以下是错误的解释，顺序如下：

d = file('test.txt','r')
text=d.read() # Ok: now 'text' contains the entire file contents.
e = file('output.txt','w')
x=raw_input("Insert word:")
# -> Comment
for line in d.readlines(): # You already read the whole file, so
# this loop can't read any more. But even without that, your input
# file only contains one line, so this would only loop once.
      if line.startswith(x): # You are trying to look for a word at the
      # beginning of each line, in order to determine where to put the
      # line breaks. But the words can't be found at the beginnings of
      # all the lines until those lines exist, i.e. after the line 
      # breaks have been positioned.
        word.append(+"\n") # This makes no sense at all. You can't 
        # '.append' to 'word' because there is no 'word' defined yet,
        # and '+"\n"' is trying to treat a string like a number. Yes,
        # you can use '+' to join two strings, but then you need one
        # on either side of the '+'. 1 + 1, "hi " + "mom".
        e.write() # If you want to write something to the file, you have
        # to specify what should be written.
        e.close() # If the loop *did* actually execute multiple times,
        d.close() # then you definitely wouldn't want to close the files
        # until after the loop is done.

---

其他答案解释了如何正确处理该问题。我们将文件读入字符串，并在单词的每个外观之前添加换行符。这相当于将单词的每个外观替换为（换行符，后跟单词）。该功能是内置的。然后，我们将修改后的字符串写入输出文件。

有几件事我没有从您的代码中得到。首先，如果您的输入文件只有一行，为什么要使用readlines（）？您的输入文件只有一行，因此d.readlines（）将在您第一次调用它时返回文件的全部内容。