Python – Removing Nested None Dictionaries

Sometimes, while working with Records, we can have a problem in which we need to perform the removal of nested records from the dictionary which are empty. This can have application in data preprocessing. Lets discuss certain ways in which this task can be performed.

Method #1 : Using dict() + filter()
This is one of the way in which this task can be performed. In this, we perform the task of filtering the None values using filter().

# Python3 code to demonstrate working of
# Removing Nested None Dictionaries
# Using filter() + dict()

# initializing dictionary
test_dict = {'gfg' : {'a': 5}, 'best' : {}, 'for' : {}, 'geeks' : {'b' : 6}}

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

# Removing Nested None Dictionaries
# Using filter() + dict()
res = dict(filter(lambda sub: sub[1], test_dict.items()))

# printing result
print("The dictionary after filtering is : " + str(res))

Output :

The original dictionary is : {‘geeks’: {‘b’: 6}, ‘for’: {}, ‘gfg’: {‘a’: 5}, ‘best’: {}}
The dictionary after filtering is : {‘geeks’: {‘b’: 6}, ‘gfg’: {‘a’: 5}}

Method #2 : Using dictionary comprehension
This is one of the way in which this task can be performed. In this we just recreate the dictionary by checking the value presence of key.

# Python3 code to demonstrate working of
# Removing Nested None Dictionaries
# Using dictionary comprehension

# initializing dictionary
test_dict = {'gfg' : {'a': 5}, 'best' : {}, 'for' : {}, 'geeks' : {'b' : 6}}

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

# Removing Nested None Dictionaries
# Using dictionary comprehension
res = {key : val for key, val in test_dict.items() if val}

# printing result
print("The dictionary after filtering is : " + str(res))

Output :

The original dictionary is : {‘geeks’: {‘b’: 6}, ‘for’: {}, ‘gfg’: {‘a’: 5}, ‘best’: {}}
The dictionary after filtering is : {‘geeks’: {‘b’: 6}, ‘gfg’: {‘a’: 5}}