嵌套字典路径按值查找答案

【问题标题】：Nested dictionary path find by value嵌套字典路径按值查找
【发布时间】：2021-11-30 21:04:50
【问题描述】：

我正在使用递归从嵌套的 JSON 中找到一些特定值的树路径。例如，在给定的 JSON 上，我试图找到 src 元素的完整路径树。 注意我有 2 个具有相同值的 src 元素，我当前的代码适用于不同的 src 值，但是当我的 src 值相同时键，结果不是预期的。

当前 JSON：

{
  "imagepanel": {
    "image": [
      {
        "scaled_image": {
          "classes": "w-full",
          "aspect_ratios": "frame sm:4:3 xmed:4:3",
          "art_directions": [
            {
              "alt": "River waves",
              "src": "path/to/file/53339c03d67e6ee5-lesson-3.jpg",
              "type": "jpg",
              "media": "(min-width:900.1px)",
              "sizes": "50vw",
              "intrinsicwidth": "1411",
              "intrinsicheight": "1000"
            },
            {
              "alt": "River waves",
              "src": "path/to/file/53339c03d67e6ee5-lesson-3.jpg",
              "type": "jpg",
              "media": "(max-width:900px)",
              "sizes": "100vw",
              "intrinsicwidth": "0",
              "intrinsicheight": "0"
            }
          ]
        }
      }
    ],
    "title": "<p><span class=\"drop-cap\" drop-cap=\"true\">WHAT TO WATCH</span></p>",
    "cta_label": "SEE THE LIST",
    "left_image": true
  }
}

当前代码：

import json
import pprint
def breadcrumb_finder(json_dict_or_list, value):
    if json_dict_or_list == value:
        return [json_dict_or_list]
    elif isinstance(json_dict_or_list, dict):
        for k, v in json_dict_or_list.items():
            child = breadcrumb_finder(v, value)
            if child:
                return [k] + child
    elif isinstance(json_dict_or_list, list):
        lst = json_dict_or_list
        for i in range(len(lst)):
            child = breadcrumb_finder(lst[i], value)
            if child:
                return [str(i)] + child

data = r'''{"imagepanel":{"image":[{"scaled_image":{"classes":"w-full","aspect_ratios":"frame sm:4:3 xmed:4:3","art_directions":[{"alt":"River waves","src":"path/to/file/53339c03d67e6ee5-lesson-3.jpg","type":"jpg","media":"(min-width:900.1px)","sizes":"50vw","intrinsicwidth":"1411","intrinsicheight":"1000"},{"alt":"River waves","src":"path/to/file/53339c03d67e6ee5-lesson-3.jpg","type":"jpg","media":"(max-width:900px)","sizes":"100vw","intrinsicwidth":"0","intrinsicheight":"0"}]}}],"title":"<p><span class=\"drop-cap\" drop-cap=\"true\">WHAT TO WATCH</span></p>","cta_label":"SEE THE LIST","left_image":true}}'''
data = json.loads(data)

all_src = ['path/to/file/53339c03d67e6ee5-lesson-3.jpg', 'path/to/file/53339c03d67e6ee5-lesson-3.jpg']
for src in all_src:
    nested_path = breadcrumb_finder(data, src)
    print(nested_path)

电流输出：

['imagepanel', 'image', '0', 'scaled_image', 'art_directions', '0', 'src', 'path/to/file/53339c03d67e6ee5-lesson-3.jpg']
['imagepanel', 'image', '0', 'scaled_image', 'art_directions', '0', 'src', 'path/to/file/53339c03d67e6ee5-lesson-3.jpg']

                                                               ^^^ note index here

预期输出：

['imagepanel', 'image', '0', 'scaled_image', 'art_directions', '0', 'src', 'path/to/file/53339c03d67e6ee5-lesson-3.jpg']
['imagepanel', 'image', '0', 'scaled_image', 'art_directions', '1', 'src', 'path/to/file/53339c03d67e6ee5-lesson-3.jpg']

                                                               ^^^ note index here

【问题讨论】：

我这里有点迷茫，如果最初找到正在搜索的同一个src，为什么要索引1？或者，如果已经找到某个索引，您是否只想跳过它？
删除已经找到的元素怎么样？
@ZaidAlShatle 我同意你的观点，但我的要求是找到给定 src 值的所有路径。因此，如果在多个地方找到 src，我需要这些多条路径:)
@ZhubeiFederer 似乎是个好主意，但不确定如何在更大的嵌套字典上有效地做到这一点。

标签： python dictionary recursion

【解决方案1】：

经过一点调试，我发现问题出在这段代码上：

elif isinstance(json_dict_or_list, list):
    lst = json_dict_or_list
    for i in range(len(lst)):
        child = breadcrumb_finder(lst[i], value)
        if child:
            return [str(i)] + child

由于child数组不为空时调用return，如果条件满足，也会忽略lst[i]之后的所有元素。

因此，我通过使用回溯稍微更改了您的代码：

import json
import pprint
results = []
def breadcrumb_finder(json_dict_or_list, value, path, result):
    if json_dict_or_list == value:
        path.append(json_dict_or_list)
        result.append(path.copy())
        path.pop()
    elif isinstance(json_dict_or_list, dict):
        for k, v in json_dict_or_list.items():
            path.append(k)
            child = breadcrumb_finder(v, value, path, result)
            path.pop()
                
    elif isinstance(json_dict_or_list, list):
        lst = json_dict_or_list
        for i in range(len(lst)):
            path.append(i)
            child = breadcrumb_finder(lst[i], value, path, result)
            path.pop()       

data = r'''{"imagepanel":{"image":[{"scaled_image":{"classes":"w-full","aspect_ratios":"frame sm:4:3 xmed:4:3","art_directions":[{"alt":"River waves","src":"path/to/file/53339c03d67e6ee5-lesson-3.jpg","type":"jpg","media":"(min-width:900.1px)","sizes":"50vw","intrinsicwidth":"1411","intrinsicheight":"1000"},{"alt":"River waves","src":"path/to/file/53339c03d67e6ee5-lesson-3.jpg","type":"jpg","media":"(max-width:900px)","sizes":"100vw","intrinsicwidth":"0","intrinsicheight":"0"}]}}],"title":"<p><span class=\"drop-cap\" drop-cap=\"true\">WHAT TO WATCH</span></p>","cta_label":"SEE THE LIST","left_image":true}}'''
data = json.loads(data)

all_src = ['path/to/file/53339c03d67e6ee5-lesson-3.jpg']
for src in all_src:
    breadcrumb_finder(data, src, [], results)
    print(results)

这将确保列表将一直迭代。结果：

[['imagepanel', 'image', 0, 'scaled_image', 'art_directions', 0, 'src', 'path/to/file/53339c03d67e6ee5-lesson-3.jpg'], ['imagepanel', 'image', 0, 'scaled_image', 'art_directions', 1, 'src', 'path/to/file/53339c03d67e6ee5-lesson-3.jpg']]

编辑：我更新了全局变量results，这样它就不会与局部变量混淆了

【讨论】：

【解决方案2】：

import json
import pprint
def breadcrumb_finder(json_dict_or_list, value):
    if json_dict_or_list == value:
        return [json_dict_or_list]
    elif isinstance(json_dict_or_list, dict):
        for k, v in json_dict_or_list.items():
            child = breadcrumb_finder(v, value)
            if child:
                return [k] + child
    elif isinstance(json_dict_or_list, list):
        lst = json_dict_or_list
        for i in range(len(lst)):
            child = breadcrumb_finder(lst[i], value)
            if child:
                if child[0] != "src" or str(i) not in found_srcs:
                    found_srcs.append(str(i))
                    return [str(i)] + child

data = r'''{"imagepanel":{"image":[{"scaled_image":{"classes":"w-full","aspect_ratios":"frame sm:4:3 xmed:4:3","art_directions":[{"alt":"River waves","src":"path/to/file/53339c03d67e6ee5-lesson-3.jpg","type":"jpg","media":"(min-width:900.1px)","sizes":"50vw","intrinsicwidth":"1411","intrinsicheight":"1000"},{"alt":"River waves","src":"path/to/file/53339c03d67e6ee5-lesson-3.jpg","type":"jpg","media":"(max-width:900px)","sizes":"100vw","intrinsicwidth":"0","intrinsicheight":"0"}]}}],"title":"<p><span class=\"drop-cap\" drop-cap=\"true\">WHAT TO WATCH</span></p>","cta_label":"SEE THE LIST","left_image":true}}'''
data = json.loads(data)

all_src = ['path/to/file/53339c03d67e6ee5-lesson-3.jpg', 'path/to/file/53339c03d67e6ee5-lesson-3.jpg']
found_srcs = []
for src in all_src:
    nested_path = breadcrumb_finder(data, src)
    print(nested_path)

通过存储找到的 src，您可以跳过它们。我发现最简单的方法是在添加 src 编号之前，您可以像在代码中一样检查并完全跳过该迭代。

输出：

['imagepanel', 'image', '0', 'scaled_image', 'art_directions', '0', 'src', 'path/to/file/53339c03d67e6ee5-lesson-3.jpg']
['imagepanel', 'image', '0', 'scaled_image', 'art_directions', '1', 'src', 'path/to/file/53339c03d67e6ee5-lesson-3.jpg']

【讨论】：