Python - Remove None Nested Records

Python – Remove None Nested Records

Last Updated : 10 May, 2020

Sometimes, while working with Python Records, can have problem in which we need to perform the removal of data which have all key’s values as None in nested records. This kind of problem can have application in data preprocessing. Lets discuss certain ways in which this task can be performed.

Method #1 : Using all() + dictionary comprehension
The combination of above functionalities can be used to solve this problem. In this, the removal of all the values with all None values are not included in dictionary re construction are done using all().

# Python3 code to demonstrate working of 
# Remove None Nested Records
# Using all() + dictionary comprehension
  
# initializing dictionary
test_dict = {'gfg' : {'a' : 1, 'b' : 2}, 
              'is' : {'d' : None, 'e' : None}, 
              'best' : {'g' : 1}}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# Remove None Nested Records
# Using all() + dictionary comprehension
res = {key: sub1 for key, sub1 in test_dict.items() if not
      all(sub2 is None for sub2 in sub1.values())}
  
# printing result 
print("The dictionary after removal : " + str(res)) 

Output :

The original dictionary is : {‘gfg’: {‘b’: 2, ‘a’: 1}, ‘is’: {‘e’: None, ‘d’: None}, ‘best’: {‘g’: 1}}
The dictionary after removal : {‘gfg’: {‘b’: 2, ‘a’: 1}, ‘best’: {‘g’: 1}}

Method #2 : Using any() + dictionary comprehension
The combination of above functions can also be used to solve this problem. In this, we keep all the records which have any key as not none using any().

# Python3 code to demonstrate working of 
# Remove None Nested Records
# Using any() + dictionary comprehension
  
# initializing dictionary
test_dict = {'gfg' : {'a' : 1, 'b' : 2}, 
              'is' : {'d' : None, 'e' : None}, 
              'best' : {'g' : 1}}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# Remove None Nested Records
# Using any() + dictionary comprehension
res = {key: sub1 for key, sub1 in test_dict.items() if 
       any(sub2 is not None for sub2 in sub1.values())}
  
# printing result 
print("The dictionary after removal : " + str(res)) 

Output :

The original dictionary is : {‘gfg’: {‘b’: 2, ‘a’: 1}, ‘is’: {‘e’: None, ‘d’: None}, ‘best’: {‘g’: 1}}
The dictionary after removal : {‘gfg’: {‘b’: 2, ‘a’: 1}, ‘best’: {‘g’: 1}}

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