Python递归函数缺少结果

Question

来自Python的递归追加列表函数，试图递归地获取与文件结构相关的权限列表。

def get_child_perms(self, folder, request, perm_list):
        # Folder contains other folders
        if folder.get_children():
            # For every sub-folder
            return [self.get_child_perms(subfolder, request, perm_list) for subfolder in folder.get_children()]
        return folder.has_read_permission(request)

folder <- Missing (allowed)
    subfolder <- Missing (restricted)
        subsubfolder <- Get this (restricted)
            files

另一种情况是，A=允许，R=限制

folder  A
    subfolder   A
        subsubfolder    R
            files
        files
    subfolder   R
        files
    subfolder   A
        subsubfolder    A
            files
        files
    subfolder   A
        files
    files

输出将是[True，True，False，False，True，True，True]

Answer 1

最基本的问题是您只返回文件夹权限，当文件夹没有任何子文件夹时，当它有子文件夹时，您没有在返回结果中包括文件夹.has_read_permission(request)，这很可能导致您出现问题。你需要做的是-

def get_child_perms(self, folder, request, perm_list):
        # Folder contains other folders
        if folder.get_children():
            # For every sub-folder
            return [folder.has_read_permission(request)] + [self.get_child_perms(subfolder, request, perm_list) for subfolder in folder.get_children()]
        return [folder.has_read_permission(request)]

这应该导致（未测试）-

[folderperm [subfolderperm [subsubfolderperm]]