Python递归追加列表函数

Question

递归函数有问题，应该相对简单，但似乎不能正确。

我有一个文件夹结构，其中的文件夹可以包含其他文件夹、图像或文件。与每个文件夹相关联的都有权限。我想让我的函数递归地构建与每个文件夹关联的权限列表。

我有一个函数 has_read_permission(request) 如果文件夹有权限则返回 True 否则返回 False

我已经构建了一个这样的函数:

def get_child_perms(self, folder, request, perm_list):
        # Folder contains other folders
        if folder.get_children():
            # For every sub-folder
            for subfolder in folder.get_children():
                return perm_list.append(self.get_child_perms(subfolder, request, perm_list))
        else:
            # If folder doesn't have sub-folders containing folders
            return [folder.has_read_permission(request)]

我一直没有得到

给定这样的文件夹:

Folder (allowed) - Wont check this one
|_First Folder (allowed)
| |_First sub Folder (restricted)
| | |_File
| | |_File
| | |_Image
| |__Second Sub Folder (allowed)
|_Second Folder (allowed)

然后运行 ​​get_child_perms() 会返回[真、假、真、真]甚至[正确，[错误，正确]，正确]

编辑

忽略编辑 -> 问其他问题 Python Recursive function missing results

改变了一点，

def get_child_perms(self, folder, request, perm_list):
        if folder.get_children():
            for subfolder in folder.get_children():
                perm_list.append(self.get_child_perms(subfolder, request, perm_list))
            return perm_list
        else:
            return [folder.has_read_permission(request)]

获得:

[[True], [...], [True], [...], [...], [True], [True], [True], [True], [True], [True], [True], [True], [...], [True], [...]]

 Admin
 -Folder 1
   - Files
 -Folder 2
   - Files
 -Folder 3
   - Files 
 -Folder 4
   - SubFolder 1
      -SubSubFolder 1
         - Files
      - Files
   - SubFolder 2
      - SubSubFolder 2
           - Files
      - Files
 -Folder 5
   - SubFolder 3
       - Files
   - SubFolder 4
       - Files
   - SubFolder 5
       -Files
   - Files
 -Folder 6
   - Files
 -Folder 7
   - SubFoler 6
       - Files
   - Files
 -Folder 8
   - Files

Answer 1

for subfolder in folder.get_children():
    perm_list.append(self.get_child_perms(subfolder, request, perm_list))
return perm_list

.append 到位。它不返回任何东西。所以你得到的是 None