解压缩嵌套词典列表并转换为CSV

Question

I am trying to write to CSV a JSON that produces a list of nested dictionnaries as follows:

[{'spam': 'xxxx',
  'egg': 'yyyy',
  'line_items': [{'description': 'hhh',
                  'amount': 'iii'},
                 {'description': 'jjj',
                  'amount': 'kkk'}],
  'bacon': 'zzzz'}]

I wrote the following code (being still very new to Python):

import csv

jsonData = json.loads(r.text)
keys = list(jsonData[0].keys())
with open(filePathCsv, 'w') as csvfile:
    w = csv.DictWriter(csvfile, keys)
    w.writeheader()
    w.writerows(jsonData)

This produces the following:

CSV output

What I need to achieve is this:

Expected output

where each nested line item produces a new row.

I imagine the best way to achieve this is to unpack my list of nested dictionnaries to a simple list of dictionnaries, like so:

[{'spam': 'xxxx',
  'egg': 'yyyy',
  'description': 'hhh',
  'amount': 'iii',
  'bacon': 'zzzz'},
 {'spam': 'xxxx',
    'egg': 'yyyy',
    'description': 'jjj',
    'amount': 'kkk',
    'bacon': 'zzzz'}]

But I am at a loss as to how to achieve this.

Or perhaps there is another way to achieve my expected result?

Answer 1

Or perhaps there is another way to achieve my expected result?

If you use pandas , there's a one-liner for this, using json_normalize :

import pandas as pd

data = [{'spam': 'xxxx',
  'egg': 'yyyy',
  'line_items': [{'description': 'hhh',
                  'amount': 'iii'},
                 {'description': 'jjj',
                  'amount': 'kkk'}],
  'bacon': 'zzzz'}]

df = pd.io.json.json_normalize(data, record_path=['line_items'],
                                meta=['spam', 'egg','bacon'])
df

  amount description   egg  spam bacon
0    iii         hhh  yyyy  xxxx  zzzz
1    kkk         jjj  yyyy  xxxx  zzzz

---

df.to_csv('out.csv')