Lookup and append new values to dictionary based on reference dictionary values

Question

I want to lookup values ("uri") from a reference dict "fulltracks" and create a new dict with updated values. Each list is going to be used to create playlists with the spotify API afterwards.

Consider this list of dictionaries, each list item displays a track:

fulltracks = [{"artists":[1,2], "uri": "xyz",} 
              {"artists":[3], "uri": "abc"},
              {"artists":[4], "uri": "nmk"}, 
              {"artists":[5], "uri": "qwe"}, 

Additionally, I have this dictionary where the values are keys (artist) from fulltracks:

genres = {
  "rock": [1],
  "pop": [2],
  "hip hop": [3,4],
  "rap": [4],
  "house": [5]}

I would like to come out at an updated version of the dictionary "genres_uris":

genres_uris = {
  "rock": ["xyz"],
  "pop": ["xyz"],
  "hip hop": ["abc", "nmk"],
  "rap": ["abc"],
  "house": ["qwe"]}

I would call it a lookup in Excel but can not get my head into the right keywords for a Python approach/search. I came across pandas for this, is this library the right solution for my problem?

Answer 1

You can use dictionary comprehension:

>>> {k: [d["uri"] for d in fulltracks for val in v if val in d["artists"]] for k, v in genres.items()}

{'rock': ['xyz'],
 'pop': ['xyz'],
 'hip hop': ['abc', 'nmk'],
 'rap': ['nmk'],
 'house': ['qwe']}