Python – Maximum Value in Nested Dictionary

Sometimes, while working with python dictionary, we can have problem in which each key in itself is a record with several keys and we desire to substitute the value as maximum value of keys of dictionary. This kind of problem can have application in many domains that involves data. Lets discuss certain ways in which this task can be performed.

Method #1 : Using loop
This is brute way in which this task can be performed. In this, we iterate for each key’s keys to get maximum value and set in resultant dictionary.

# Python3 code to demonstrate working of
# Maximum Value in Nested Dictionary
# Using loop

# initializing dictionary
test_dict = {'gfg' : {'a' : 15, 'b' : 14},
             'is' : {'d' : 2, 'e' : 10, 'f' :  3},
             'best' : {'g' : 19}}

# printing original dictionary
print("The original dictionary is : " + str(test_dict))

# Maximum Value in Nested Dictionary
# Using loop
res = {}
for key, val in test_dict.items():
    max_val = 0
    for ele in val.values():
        if ele > max_val:
            max_val = ele
    res[key] = max_val

# printing result
print("The modified dictionary : " + str(res))

Output :

The original dictionary is : {‘is’: {‘f’: 3, ‘e’: 10, ‘d’: 2}, ‘gfg’: {‘a’: 15, ‘b’: 14}, ‘best’: {‘g’: 19}}
The modified dictionary : {‘best’: 19, ‘is’: 10, ‘gfg’: 15}

Method #2 : Using max() + dictionary comprehension
This is yet another way in which this task can be performed. In this, we perform the task of extracting maximum using max() and dictionary comprehension is used to iterate and construct new dictionary.

# Python3 code to demonstrate working of
# Maximum Value in Nested Dictionary
# Using max() + dictionary comprehension

# initializing dictionary
test_dict = {'gfg' : {'a' : 15, 'b' : 14},
             'is' : {'d' : 2, 'e' : 10, 'f' :  3},
             'best' : {'g' : 19}}

# printing original dictionary
print("The original dictionary is : " + str(test_dict))

# Maximum Value in Nested Dictionary
# Using max() + dictionary comprehension
res = {key: max(val.values()) for key, val in test_dict.items()}

# printing result
print("The modified dictionary : " + str(res))

Output :

The original dictionary is : {‘is’: {‘f’: 3, ‘e’: 10, ‘d’: 2}, ‘gfg’: {‘a’: 15, ‘b’: 14}, ‘best’: {‘g’: 19}}
The modified dictionary : {‘best’: 19, ‘is’: 10, ‘gfg’: 15}