在 Jinja2 的嵌套字典中显示所有键的映射答案

【问题标题】：displaying a mapping of all keys in a nested dictionary in Jinja2在 Jinja2 的嵌套字典中显示所有键的映射
【发布时间】：2022-06-16 12:48:21
【问题描述】：

我还是 Jinja 的新手，所以如果我的问题措辞不当，请提前道歉。我正在尝试显示访问嵌套字典中特定值所需的键的映射。我希望输出显示字典的键，箭头指向下一个嵌套键，依此类推key1 --> key2 --> key3 --> value

我正在使用的字典如下所示：

x = {
      "food": {},
      "dessert": {},
      "vehicles": {
        "trucks": {},
        "cars": {
          "brands": {
            "german brands": ["Audi", "BMW"],
            "american brands": ["Dodge", "Chevy"]
          },
          "seats": {
            "types": ["leather"]
          }
        },
        "color": ["black", "white"]
      },
      "electronics": {"laptops": {}}
  }

我希望输出以如下格式显示结果：

food --> {}
dessert --> {}
vehicles --> trucks --> {}
vehicles --> cars --> brands --> german brands --> Audi
vehicles --> cars --> brands --> german brands --> BMW
vehicles --> cars --> brands --> american brands --> Dodge
vehicles --> cars --> brands --> american brands --> Chevy
vehicles --> cars --> seats --> types --> leather
vehicles --> color--> black
vehicles --> color--> white
electronics --> laptops --> {}

我的代码可以做到这一点，但它只检查最终值是否是一个列表并打印列表及其关联的键（它不打印之前导致它的嵌套键，仅与值关联的键）。

<table style="width:100%">
  <tr>
    <th>Nested Items Table</th>
  </tr>
  {% for key, value in _.x.items() recursive %}
    {% if value is mapping %}
      {{ loop(value.items()) }}
    {% else %}
      <tr>
      <td>{{ key }} --> {{ value }}</td>
      </tr>
    {% endif %}
  {% endfor %}
</table>

如果你运行上面的代码，我想你会明白我的意思。如果有人能够帮助我，或者可能引导我朝着正确的方向前进，我将不胜感激！

【问题讨论】：

标签： python jinja2

【解决方案1】：

我建议你使用自定义过滤器来避免 jinja2 中的递归错误：（这里是循环）

import jinja2

x = {
      "food": {},
      "dessert": {},
      "vehicles": {
        "trucks": {},
        "cars": {
          "brands": {
            "german brands": ["Audi", "BMW"],
            "american brands": ["Dodge", "Chevy"]
          },
          "seats": {
            "types": ["leather"]
          }
        },
        "color": ["black", "white"]
      },
      "electronics": {"laptops": {}}
  }


def looping(z):
    """Custom filter"""


    def islist(v):
        return type(v) == list

    def isdict(v):
        return type(v) == dict

    def islord(v):
        return type(v) == dict or type(v) == list

    def loopover(v, kk):
        global result
        for key, value in v.items():
            k = "<td>" + key + " --> "

            if islord(value):
                if value == {}:
                    result = result + kk + k + "{}" + '</td>\n'

                elif value == []:
                    result = result + kk + k + "[]" + '</td>\n'

                elif isdict(value):
                    loopover(value, k)
                elif islist(value):
                    for it in value:
                        result = result + kk + it + '</td>\n'

            else:
                result = result + kk + k + value + '</td>\n'

    loopover(z, "")
    return result

result = ""
loader = jinja2.FileSystemLoader(searchpath='.')
env = jinja2.Environment(autoescape=True, loader=loader)
env.filters['looping'] = looping

temp = env.get_template('template.html')

result = temp.render(x=x)  
print(result)

与程序python在同一文件夹中的文件template.html：

<table style="width:100%">
  <tr>
    <th>Nested Items Table</th>
  </tr>
      <tr>
      {{x | looping|safe}}
      </tr>

</table>

结果：

<table style="width:100%">
  <tr>
    <th>Nested Items Table</th>
  </tr>
      <tr>
      <td>food --> {}</td>
<td>dessert --> {}</td>
<td>vehicles --> <td>trucks --> {}</td>
<td>brands --> Audi</td>
<td>brands --> BMW</td>
<td>brands --> Dodge</td>
<td>brands --> Chevy</td>
<td>seats --> leather</td>
<td>vehicles --> black</td>
<td>vehicles --> white</td>
<td>electronics --> <td>laptops --> {}</td>
      </tr>
</table>

【讨论】：