Python：使用特定条件从文件中删除行

Question

我尝试使用某些条件从文件中删除行，但是当我运行脚本时，它只删除整个文件。当我将脚本更改为“只读”＆＃39;它返回带有搜索条件的行但是当我在＆＃39;中写入＆＃39;模式它并从打印每一行改变它以删除每一行它清空整个事物。

#!/usr/bin/env python

f = raw_input('Enter filename > ')

with open(f, 'w+') as fobj:
    criteria = raw_input('Enter criteria > ')
    for eachLine in fobj:
        if criteria in eachLine:
            fobj.remove(eachLine)
            break


fobj.close()

Answer 1

我希望您想删除具有特定条件的行。您只需创建另一个文件，然后在该文件中写入内容，如下所示：

<div class="tags">
                @foreach ($tags as $tag)
                    <span class="label label-default">{{ $tag }}</span>
                @endforeach
</div>

Answer 2

来自文档：

w+ Open for reading and writing.  The file is created if it does not
   exist, otherwise it is truncated.  The stream is positioned at
   the beginning of the file.
a+ Open for reading and writing.  The file is created if it does not
   exist.  The stream is positioned at the end of the file.  Subse-
   quent writes to the file will always end up at the then current
   end of file, irrespective of any intervening fseek(3) or similar.

所以你在截断包含with open的行上的文件。您可能想要创建一个具有不同名称的新文件，并在程序结束时将其重命名。