使用 os.walk() 加入子目录

Question

with open('images.txt', 'w') as text_file:
    for folderName, subfolders, f in os.walk(root_folder):
        for subfolder in subfolders:
            if subfolder == 'image_02':
                left_path = os.path.join(folderName, subfolder, 'data')
                left_list = [f for f in sorted(os.listdir(left_path)) if
                             not f.startswith('.') and f.endswith('.png')]
            elif subfolder == 'image_03':
                right_path = os.path.join(folderName, subfolder, 'data')
                right_list = [f for f in sorted(os.listdir(right_path)) if
                              not f.startswith('.') and f.endswith('.png')]
    if len(left_list) != len(right_list):
        print('ERROR: directory {} does not match with {}'.format(left_path, right_path))
        continue

    for left_file, right_file in zip(left_list, right_list):
        text_file.write(
            os.path.join(left_path, left_file) + " " + os.path.join(right_path, right_file) + "\n")

I can not access the left_list and right_list to join their paths as certainly they are out of scope.
Could anyone tell how to fix this with a better code structure?

Answer 1

You could initialize the lists outside of the for

with open('images.txt', 'w') as text_file:
    left_list = []
    right_list = []

    for folderName, subfolders, f in os.walk(root_folder):
        for subfolder in subfolders:
            if subfolder == 'image_02':
                left_path = os.path.join(folderName, subfolder, 'data')
                left_list = [f for f in sorted(os.listdir(left_path)) if
                         not f.startswith('.') and f.endswith('.png')]
            elif subfolder == 'image_03':
                right_path = os.path.join(folderName, subfolder, 'data')
                right_list = [f for f in sorted(os.listdir(right_path)) if
                          not f.startswith('.') and f.endswith('.png')]
    if len(left_list) != len(right_list):
        print('ERROR: directory {} does not match with {}'.format(left_path, right_path))
        continue

    for left_file, right_file in zip(left_list, right_list):
        text_file.write(
        os.path.join(left_path, left_file) + " " + os.path.join(right_path, right_file) + "\n")

Answer 2

    with open(dataset['destination'], 'w') as text_file:
        left_list = []
        right_list = []

        for folderName, subfolders, f in os.walk(root_folder):
            for subfolder in subfolders:
                if subfolder == 'image_02':
                    left_path = os.path.join(folderName, subfolder, 'data')
                    for f in sorted(os.listdir(left_path)):
                        if not f.startswith('.') and f.endswith('.png'):
                            left_list.append(f)
                elif subfolder == 'image_03':
                    right_path = os.path.join(folderName, subfolder, 'data')
                    for f in sorted(os.listdir(right_path)):
                        if not f.startswith('.') and f.endswith('.png'):
                            right_list.append(f)

        if len(left_list) != len(right_list):
            print('ERROR: directory {} does not match with {}'.format(left_path, right_path))
            continue

        for left_file, right_file in zip(left_list, right_list):
            text_file.write(
                os.path.join(left_path, left_file) + " " + os.path.join(right_path, right_file) + "\n")

This would be a better way!