CODEWITHSUNDEEP
pythonpython-2.7dictionarynested
Gary
Gary

Reputation: 129

Create Nested Dictionary From Flat Dictionary

I have the following dictionary in which keys are parent classes and values are a list of child classes which inherit from them.

{
    "Animal": 
        ["Dog"]
    ,  
    "Dog": 
        ["Labrador"]
    , 
    "Vehicle": 
        ["PetrolCar", 
        "DieselCar"]
    ,
    "DieselCar": 
        ["Hyundai"]
    , 
    "PetrolCar": 
        ["Hyundai", 
        "Ford"]
}

As you can see, some of the parent classes are also children of another parent class (deep inheritance), i.e. Animal -> Dog -> Labrador

How can I format this so that the output represents the levels of inheritance, something like this:

{
    "Animal": {
        "Dog": { 
            "Labrador": []
        }
    }, 
    "Vehicle": {
        "PetrolCar": {
            "Hyundai": [], 
            "Ford": []
        },
        "DieselCar": { 
            "Hyundai": []
        }
    }
}

I also want to be able to extend the provided dataset by adding more parents or children. For example: Adding ElectricCar as a child of Vehicle and Tesla as a child of ElectricCar. And adding Cat as a child of Animal, with no children of it's own.

Input:

{
    "Animal": 
        ["Dog",
        "Cat"]
    ,  
    "Dog": 
        ["Labrador"]
    , 
    "Vehicle": 
        ["PetrolCar", 
        "DieselCar",
        "ElectricCar"]
    ,
    "DieselCar": 
        ["Hyundai"]
    , 
    "PetrolCar": 
        ["Hyundai", 
        "Ford"]
    ,
    "ElectricCar": 
        ["Tesla"]
}

Output:

{
    "Animal": {
        "Dog": { 
            "Labrador": []
        },
        "Cat": []
    }, 
    "Vehicle": {
        "PetrolCar": {
            "Hyundai": [], 
            "Ford": []
        },
        "DieselCar": { 
            "Hyundai": []
        },
        "ElectricCar": { 
            "Tesla": []
        }
    }
}

Upvotes: 3

Views: 220

Answers (1)

Ajax1234
Ajax1234

Reputation: 71451

You can use recursion to produce the nested dictionary, and then remove keys that do not have any children:

data = {'Animal': ['Dog', 'Cat'], 'Dog': ['Labrador'], 'Vehicle': ['PetrolCar', 'DieselCar', 'ElectricCar'], 'DieselCar': ['Hyundai'], 'PetrolCar': ['Hyundai', 'Ford'], 'ElectricCar': ['Tesla']}
def build(key):
  return {i:[] if i not in data else build(i) for i in data[key]}

results = {i:build(i) for i in data}

import json
print(json.dumps({a:b for a, b in results.items() if any(h for h in b.values())}, indent=4))

Output:

{
  "Animal": {
    "Dog": {
        "Labrador": []
    },
    "Cat": []
  },
  "Vehicle": {
    "PetrolCar": {
        "Hyundai": [],
        "Ford": []
     },
     "DieselCar": {
        "Hyundai": []
     },
     "ElectricCar": {
        "Tesla": []
     }
   }
}

Upvotes: 5

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