group_items.py

from pydantic import BaseModel
from typing import List

class InputItem(BaseModel):
    song_id: str
    audio_filename: str
      
class OutputItem(BaseModel):
    song_id: str
    audio_filenames: list # of strs
      
data_in = [
    {
        'song_id': i % 2,
        'audio_filename': f'track-{i}.mp3',
    }
    for i in range(5)
]


input_items = [InputItem.parse_obj(song_dict) for song_dict in data_in]


def output_items(input_items: List[InputItem]) -> List[OutputItem]:

    song_ids = set(item.song_id for item in input_items)

    return [
        OutputItem(
            song_id=song_id,
            audio_filenames=[
                item.audio_filename
                for item in input_items
                if item.song_id == song_id
            ],
        )
        for song_id in song_ids
    ]

print('INPUT ITEMS')
for ii in input_items:
    print(ii.json(indent=2))

print('OUTPUT ITEMS')
for oi in output_items(input_items):
    print(oi.json(indent=2))

python:
  group_items_demo:
    screenshots: group_items_demo/*.png
    code: https://gist.github.com/ryantuck/168a52a1dab6ab3ecf941c3960ff73c4