Python 使用“with open() as file”方法，怎么写不止一次？
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Using "with open() as file" method, how to write more than once?
提问by O.rka
Usually to write a file, I would do the following:
通常要写一个文件，我会做以下事情：
the_file = open("somefile.txt","wb")
the_file.write("telperion")
but for some reason, iPython (Jupyter) is NOT writing the files. It's pretty weird, but the only way I could get it to work is if I write it this way:
但出于某种原因，iPython (Jupyter) 没有写入文件。这很奇怪，但我可以让它工作的唯一方法是我这样写：
with open('somefile.txt', "wb") as the_file:
the_file.write("durin's day\n")
with open('somefile.txt', "wb") as the_file:
the_file.write("legolas\n")
But obviously it's going to recreate the file object and rewrite it.
但显然它会重新创建文件对象并重写它。
Why does the code in the first block not work? How could I make the second block work?
为什么第一个块中的代码不起作用？我怎样才能使第二个块工作？
回答by Antti Haapala
The wflag means "open for writing and truncate the file"; you'd probably want to open the file with the aflag which means "open the file for appending".
该w标志的意思是“打开写入并截断文件”；你可能想用a标志打开文件，这意味着“打开文件进行附加”。
Also, it seems that you're using Python 2. You shouldn't be using the bflag, except in case when you're writing binary as opposed to plain text content. In Python 3 your code would produce an error.
此外，您似乎使用的是 Python 2。您不应该使用该b标志，除非您正在编写二进制而不是纯文本内容。在 Python 3 中，您的代码会产生错误。
Thus:
因此：
with open('somefile.txt', 'a') as the_file:
the_file.write("durin's day\n")
with open('somefile.txt', 'a') as the_file:
the_file.write("legolas\n")
As for the input not showing in the file using the filehandle = open('file', 'w'), it is because the file output is buffered - only a bigger chunk is written at a time. To ensure that the file is flushed at the end of a cell, you can use filehandle.flush()as the last statement.
至于使用 没有在文件中显示的输入filehandle = open('file', 'w')，这是因为文件输出被缓冲 - 一次只写入更大的块。为确保在单元格末尾刷新文件，您可以将其filehandle.flush()用作最后一条语句。
