How to search a nested dictionary for a given value

Question

I have a dictionary that looks like this:

{'Week 1': {'Game1': {'Away': 'Team3', 'Home': 'Team2', 'Venue': 5},
            'Game2': {'Away': 'Team1', 'Home': 'Team4', 'Venue': 6}},
 'Week 2': {'Game1': {'Away': 'Team1', 'Home': 'Team2', 'Venue': 4},
            'Game2': {'Away': 'Team4', 'Home': 'Team3', 'Venue': 1}},
 'Week 3': {'Game1': {'Away': 'Team1', 'Home': 'Team3', 'Venue': 6},
            'Game2': {'Away': 'Team2', 'Home': 'Team4', 'Venue': 4}} 
...}

The dictionary contains fixture seperated by 'Week', 'Game' then 'Home', 'Away' and 'Venue'.

Say I was looking to search for all fixtures for 'Team 1' from the dictionary above and get an output of:

{'Week 1': {'Game 2': {'Away: ': 'a', 'Home: ': 'd', 'Rink ': 6}},
 'Week 2': {'Game1': {'Away: ': 'a', 'Home: ': 'b', 'Rink ': 4}},
 'Week 3': {'Game1': {'Away: ': 'a', 'Home: ': 'c', 'Rink ': 6}}}

What would be the best way to do this?

I've tried using for loops

for week, games in dict:
    for game, details in games:
        for k, v in details:
            if v == 'Team1'
               newDict.update({week: {game: details}})

But i get ValueError: too many values to unpack

Am I on the right lines, or totally off base? Any help would be greatly appreciated

`for game, details in games.items()`, `for k, v in details.items()`. Btw, do not use `dict` as variable name, you're shadowing class. — Olvin Roght, Aug 10 '20 at 09:44
Olvin has this correct - if you use `.items()` on your dictionary calls your code should work. Nicely written question by the way - clear, complete, and well written! — PirateNinjas, Aug 10 '20 at 09:46
Thanks for your comment Olvin. I have tried you method but I get: ``` or week, games in schedule: ValueError: too many values to unpack (expected 2) ```. I have also taken your advise on not using ``` dict ``` as a variable name. — MrRBM97, Aug 10 '20 at 10:07
You'll need to do `for week, games in dict.items()` as well. Basically, if you iterate over a dictionary it iterates over the dictionary keys only. If you need the key-value pairs, you should use `items`, which gives you the key and value for each item in the dictionary. — PirateNinjas, Aug 10 '20 at 10:11

score 0 · Answer 1 · answered Aug 10 '20 at 09:51

0

Dict Comprehension:

{match: {game: details} for match, games in a.items() for game, details in games.items() for k, v in details.items() if v == 'Team1'}

answered Aug 10 '20 at 09:51

mustafasencer

723
4
12

1

This is correct, but a triply nested comprehension is going to be REALLY hard to reason about and understand. – PirateNinjas Aug 10 '20 at 09:57
You are quite right about it. I provided the answer to suggest another perspective/method to our friend's issue. – mustafasencer Aug 10 '20 at 10:01

rudolfovic · Answer 2 · 2020-08-10T10:45:07.513

0

You can also just do:

{
  week: {game: info}
  for week, games in weeks
  for game, info in games
  if team in (info['Away'], info['Home'])
}

Putting it all together:

>>> weels = {'Week 1': {'Game1': {'Away': 'Team3', 'Home': 'Team2', 'Venue': 5},
...             'Game2': {'Away': 'Team1', 'Home': 'Team4', 'Venue': 6}},
...  'Week 2': {'Game1': {'Away': 'Team1', 'Home': 'Team2', 'Venue': 4},
...             'Game2': {'Away': 'Team4', 'Home': 'Team3', 'Venue': 1}},
...  'Week 3': {'Game1': {'Away': 'Team1', 'Home': 'Team3', 'Venue': 6},
...             'Game2': {'Away': 'Team2', 'Home': 'Team4', 'Venue': 4}} }
>>> team = 'Team1'
>>> {week: {game: info}
...   for week, games in weeks
...   for game, info in games
...   if team in (info['Away'], info['Home'])}
{'Week 1': {'Game2': {'Away': 'Team1', 'Home': 'Team4', 'Venue': 6}}, 'Week 2': {'Game1': {'Away': 'Team1', 'Home': 'Team2', 'Venue': 4}}, 'Week 3': {'Game1': {'Away': 'Team1', 'Home': 'Team3', 'Venue': 6}}}

edited Aug 10 '20 at 10:45

answered Aug 10 '20 at 09:53

rudolfovic

3,163
2
14
38

this would work, but it's quite hard to read and reason about. The key point in the question is that the questioner is missing "items". Not a problem here as you use the keys directly. – PirateNinjas Aug 10 '20 at 09:56
It may look difficult to read and reason about in the terminal, I've extracted the comprehension itself out into a separate block. Mapping and filtering is actually exactly what it's there for. – rudolfovic Aug 10 '20 at 09:59
1

@rudolfovic, you're slowing down your code by accessing to values using keys, it will be better to iterate over keys and values using `dict.items()`. – Olvin Roght Aug 10 '20 at 10:01

edd313 · Answer 3 · 2023-01-03T17:37:46.323

You can use a NestedDict and avoid using nested for loops or comprehensions.

from ndicts import NestedDict

d = {'Week 1': {'Game1': {'Away': 'Team3', 'Home': 'Team2', 'Venue': 5},
                'Game2': {'Away': 'Team1', 'Home': 'Team4', 'Venue': 6}},
     'Week 2': {'Game1': {'Away': 'Team1', 'Home': 'Team2', 'Venue': 4},
                'Game2': {'Away': 'Team4', 'Home': 'Team3', 'Venue': 1}},
     'Week 3': {'Game1': {'Away': 'Team1', 'Home': 'Team3', 'Venue': 6},
                'Game2': {'Away': 'Team2', 'Home': 'Team4', 'Venue': 4}}}
nd = NestedDict()

nd_team1 = {}
for key, value in nd.items():
    if value == "Team1":
            team1_record = nd.extract[key[:-1]]
            nd_team1.update(team1_record)

>>> nd_team1.to_dict()
{'Week 1': {'Game2': {'Away': 'Team1', 'Home': 'Team4', 'Venue': 6}},
 'Week 2': {'Game1': {'Away': 'Team1', 'Home': 'Team2', 'Venue': 4}},
 'Week 3': {'Game1': {'Away': 'Team1', 'Home': 'Team3', 'Venue': 6}}}

To install ndicts pip install ndicts

How to search a nested dictionary for a given value

3 Answers3