Python - Inner Nested Value List Mean in Dictionary

Python – Inner Nested Value List Mean in Dictionary

Last Updated : 14 May, 2020

Sometimes, while working with Python Dictionaries, we can have a problem in which we need to extract the mean of nested value lists in dictionary. This problem can have application in many domains including web development and competitive programming. Lets discuss certain ways in which this task can be performed.

Method #1 : Using mean() + loop
The combination of above functions provide the brute way to solve this problem. In this, we perform the task of finding mean using inbuilt mean() library and iterate for nesting using loop.

# Python3 code to demonstrate working of 
# Inner Nested Value List Mean in Dictionary
# Using mean() + loop
from statistics import mean
  
# initializing dictionary
test_dict = {'Gfg' : {'a' : [1, 5, 6, 7], 'b' : [6, 7, 8, 9]}, 'is' : {'best' :[2, 8, 9, 0]}}
  
# printing original dictionary
print("The original dictionary : " + str(test_dict))
  
# Inner Nested Value List Mean in Dictionary
# Using mean() + loop
for sub in test_dict.values():
    for key in sub:
        sub[key] = mean(sub[key])
  
# printing result 
print("The modified dictionary : " + str(test_dict)) 

Output :

The original dictionary : {‘Gfg’: {‘a’: [1, 5, 6, 7], ‘b’: [6, 7, 8, 9]}, ‘is’: {‘best’: [2, 8, 9, 0]}}
The modified dictionary : {‘Gfg’: {‘a’: 4.75, ‘b’: 7.5}, ‘is’: {‘best’: 4.75}}

Method #2 : Using dictionary comprehension + mean()
This is yet another way to solve this problem. In this, we perform similar task as above method. But difference is that in compact way and as one-liner.

# Python3 code to demonstrate working of 
# Inner Nested Value List Mean in Dictionary
# Using dictionary comprehension + mean()
from statistics import mean
  
# initializing dictionary
test_dict = {'Gfg' : {'a' : [1, 5, 6, 7], 'b' : [6, 7, 8, 9]}, 'is' : {'best' :[2, 8, 9, 0]}}
  
# printing original dictionary
print("The original dictionary : " + str(test_dict))
  
# Inner Nested Value List Mean in Dictionary
# Using dictionary comprehension + mean()
res = {idx: {key: mean(idx) for key, idx in j.items()} for idx, j in test_dict.items()}
  
# printing result 
print("The modified dictionary : " + str(res)) 

Output :

The original dictionary : {‘Gfg’: {‘a’: [1, 5, 6, 7], ‘b’: [6, 7, 8, 9]}, ‘is’: {‘best’: [2, 8, 9, 0]}}
The modified dictionary : {‘Gfg’: {‘a’: 4.75, ‘b’: 7.5}, ‘is’: {‘best’: 4.75}}

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