CODEWITHSUNDEEP
python
nsJHDM
nsJHDM

Reputation: 21

Finding a parent key from a dict given an intermediate key using python

I have a dictionary that looks like this:

d = {'dev':
        {<dev1>:
             {'mod':
                 {<mod1>:
                     {'port': [1, 2, 3]
                            }
                  }
              }
         <dev2>:
             {'mod':
                 {<mod3>:
                       {'port': [] }
                 }
             }
       }
  }

I want to be able to write a function, such that if i provide a search object such as 'mod1', it provides me the parent key as 'dev1'.

I have searched all over and tried a bunch of things, but couldnt seem to get this to work. Any help will be appreciated!

I have tried the stuff mentioned at the link below:

Python--Finding Parent Keys for a specific value in a nested dictionary

Find a key in a python dictionary and return its parents

Upvotes: 0

Views: 4260

Answers (1)

Claudiu
Claudiu

Reputation: 229361

This should work:

def find_parent_keys(d, target_key, parent_key=None):
  for k, v in d.items():
    if k == target_key:
      yield parent_key
    if isinstance(v, dict):
      for res in find_parent_keys(v, target_key, k):
        yield res

Usage:

d = {
  'dev': {
    'dev1': {
      'mod': {
        'mod1': {'port': [1, 2, 3]},
      },
    },
    'dev2': {
      'mod': {
        'mod3': {'port': []},
      },
    },
  },
}

print list(find_parent_keys(d, 'mod'))
print list(find_parent_keys(d, 'dev'))

Output:

['dev2', 'dev1']
[None]

Upvotes: 1

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