在嵌套的 for 循环中就地修改文件

Question

我在修改每个文件的同时迭代其中的目录和文件。我希望在之后立即读取 new modified 文件。这是我的代码和描述性注释：

# go through each directory based on their ids
for id in id_list:
    id_dir = os.path.join(ouput_dir, id)
    os.chdir(id_dir)

    # go through all files (with a specific extension)
    for filename in glob('*' + ext):

        # modify the file by replacing all new-line characters with an empty space
        with fileinput.FileInput(filename, inplace=True) as f:
            for line in f:
                print(line.replace('\n', ' '), end='')

        # here I would like to read the NEW modified file
        with open(filename) as newf:
            content = newf.read()

就目前而言，newf 不是新修改的，而是原来的 f。我想我明白为什么会这样，但是我发现很难克服这个问题。

我总是可以做 2 次单独的迭代（根据它们的 ID 遍历每个目录，遍历所有文件（具有特定扩展名）并修改文件，然后重复迭代以读取它们中的每一个）但是我希望是否有更有效的解决方法。也许如果有可能 restart 第二个 for 循环在修改发生后发生 read （这样至少可以避免重复外 for 循环）。

任何 ideas/designs 以干净高效的方式实现上述目标？

Answer 1

我并不是说您执行此操作的方式不正确，但我觉得您过于复杂了。这是我超级简单的解决方案。

import glob, fileinput
for filename in glob('*' + ext):

    f_in = (x.rstrip() for x in open(filename, 'rb').readlines()) #instead of trying to modify in place we instead read in data and replace raw_values.
    with open(filename, 'wb') as f_out: # we then write the data stream back out     
    #extra modification to the data can go here, i just remove the /r and /n and write back out
        for i in f_in:
            f_out.write(i)

    #now there is no need to read the data back in because we already have a static referance to it.

Answer 2

对我来说，它适用于此代码：

#!/usr/bin/env python3
import os
from glob import glob
import fileinput

id_list=['1']
ouput_dir='.'
ext = '.txt'
# go through each directory based on their ids
for id in id_list:
    id_dir = os.path.join(ouput_dir, id)
    os.chdir(id_dir)

    # go through all files (with a specific extension)
    for filename in glob('*' + ext):

        # modify the file by replacing all new-line characters with an empty space
        for line in  fileinput.FileInput(filename, inplace=True):
            print(line.replace('\n', ' ') , end="")

        # here I would like to read the NEW modified file
        with open(filename) as newf:
            content = newf.read()
        print(content)

注意我是如何遍历这些行的！

在嵌套的 for 循环中就地修改文件

Modifying a file in-place inside nested for loops

python

python-3.x

for-loop

in-place