Python递归文件夹读取

Question

我有 C++/Obj-C 背景，我刚刚发现 Python(已经写了大约一个小时)。我正在编写一个脚本来递归读取文件夹结构中文本文件的内容。

我遇到的问题是我编写的代码仅适用于一个文件夹深处。我可以看到为什么在代码中(参见 #hardcoded path)，我只是不知道如何继续使用 Python，因为我对它的体验只是全新的。

Python 代码:

import os
import sys

rootdir = sys.argv[1]

for root, subFolders, files in os.walk(rootdir):

    for folder in subFolders:
        outfileName = rootdir + "/" + folder + "/py-outfile.txt" # hardcoded path
        folderOut = open( outfileName, 'w' )
        print "outfileName is " + outfileName

        for file in files:
            filePath = rootdir + '/' + file
            f = open( filePath, 'r' )
            toWrite = f.read()
            print "Writing '" + toWrite + "' to" + filePath
            folderOut.write( toWrite )
            f.close()

        folderOut.close()

Answer 1

确保你理解os.walk的三个返回值:

for root, subdirs, files in os.walk(rootdir):

有以下含义:

• root:“遍历”的当前路径
• subdirs:root 类型目录的文件
• files:root(不在subdirs)中的非目录类型的文件

请使用 os.path.join 而不是用斜杠连接!你的问题是 filePath = rootdir + '/' + file - 你必须连接当前的“walked”文件夹而不是最上面的文件夹。所以那一定是filePath = os.path.join(root, file)。 BTW "file"是一个内置的，所以你通常不使用它作为变量名。

另一个问题是你的循环，应该是这样的，例如:

import os
import sys

walk_dir = sys.argv[1]

print('walk_dir = ' + walk_dir)

# If your current working directory may change during script execution, it's recommended to
# immediately convert program arguments to an absolute path. Then the variable root below will
# be an absolute path as well. Example:
# walk_dir = os.path.abspath(walk_dir)
print('walk_dir (absolute) = ' + os.path.abspath(walk_dir))

for root, subdirs, files in os.walk(walk_dir):
    print('--\nroot = ' + root)
    list_file_path = os.path.join(root, 'my-directory-list.txt')
    print('list_file_path = ' + list_file_path)

    with open(list_file_path, 'wb') as list_file:
        for subdir in subdirs:
            print('\t- subdirectory ' + subdir)

        for filename in files:
            file_path = os.path.join(root, filename)

            print('\t- file %s (full path: %s)' % (filename, file_path))

            with open(file_path, 'rb') as f:
                f_content = f.read()
                list_file.write(('The file %s contains:\n' % filename).encode('utf-8'))
                list_file.write(f_content)
                list_file.write(b'\n')

如果您不知道，文件的 with 语句是简写:

with open('filename', 'rb') as f:
    dosomething()

# is effectively the same as

f = open('filename', 'rb')
try:
    dosomething()
finally:
    f.close()