How to export a weighted edge list to a JSON tree?

Question

Given the following Pandas DataFrame (the original DataFrame has 200+ rows):

import pandas as pd
df = pd.DataFrame({
    'child': ['Europe', 'France', 'Paris','North America', 'US', 'Canada'],
    'parent': ["", 'Europe', 'France',"", 'North America', 'North America'],
    'value': [746.4, 67.75, 2.16, 579,331.9, 38.25]
})

df

|---+---------------+---------------+--------|
|   | child         | parent        |  value |
|---+---------------+---------------+--------|
| 0 | Europe        |               | 746.40 |
| 1 | France        | Europe        |  67.75 |
| 2 | Paris         | France        |   2.16 |
| 3 | North America |               | 579.00 |
| 4 | US            | North America | 331.90 |
| 5 | Canada        | North America |  38.25 |
|---+---------------+---------------+--------|

I want to generate the following JSON tree:

  [
      {
      name: 'Europe',
      value: 746.4,
      children: [
          {
          name: 'France',
          value: 67.75,
          children: [
              {
              name: 'Paris',
              value: 2.16
              }
          ]
          }
      ]
      },
      {
      name: 'North America',
      value: 579,
      children: [
          {
          name: 'US',
          value: 331.9,
          },
          {
          name: 'Canada',
          value: 38.25
          }
      ]
      }
  ];

This tree will be used as an input for ECharts visualizations, like for example this basic sunburst chart.

Answer 1

There is a library called bigtree which can do exactly what you are looking for.

import json
import bigtree

# Set the parent values for children without parents to ROOT
df["parent"] = df["parent"].replace(r'^$', "ROOT", regex = True)

tree = bigtree.dataframe_to_tree_by_relation(df, "child", "parent")
# tree.show(all_attrs = True)

# Convert to dict and discard the ROOT key
tree_dict = bigtree.tree_to_nested_dict(tree, all_attrs = True)["children"]

# Convert the dict to the desired string format
print(json.dumps(tree_dict, indent = 2))

Also see: Read data from a pandas DataFrame and create a tree using anytree in python