Python - Remove K valued key from Nested Dictionary

Sometimes, while working with records, we can have a problem in which we need to perform the removal of a key from nested dictionary whose value us specific to K. This is a common problem and has its application in data domains such as web development. Lets discuss certain ways in which this task can be performed.

Input : test_dict = {‘CS’: {‘priceless’: 6}, ‘is’: {‘better’: 6}, ‘gfg’: {‘best’: 6}}
Output : {‘CS’: {}, ‘gfg’: {}, ‘is’: {}}

Input : test_dict = {‘CS’: {‘priceless’: 9}, ‘is’: {‘better’: 8}, ‘gfg’: {‘best’: 7}}
Output : {‘CS’: {‘priceless’: 9}, ‘is’: {‘better’: 8}, ‘gfg’: {‘best’: 7}}

Method #1 : Using loop + isinstance() + filter()
The combination of above functions can be used to solve this problem. In this, we perform the task of K value using filter() and isinstance() is used to test for nesting dictionary. The dictionary construction is done using loop.

# Python3 code to demonstrate working of  
# Remove K valued key from Nested Dictionary 
# Using loop + isinstance() + filter() 
  
# initializing dictionary 
test_dict = {'gfg' : {'best' : 4, 'good' : 5},  
             'is' : {'better' : 6, 'educational' : 4}, 
             'CS' : {'priceless' : 6}} 
  
# printing original dictionary 
print("The original dictionary : " + str(test_dict)) 
  
# initializing rem_val 
rem_val = 6
  
# Remove K valued key from Nested Dictionary 
# Using loop + isinstance() + filter() 
def rem_vals(ele): 
  global rem_val 
  key, val = ele 
  return val != rem_val 
  
res = dict() 
for key, val in test_dict.items(): 
  if isinstance(val, dict): 
    res[key] = dict(filter(rem_vals, val.items())) 
  else: 
    res[key] = val 
  
# printing result  
print("Dictionary after removal : " + str(res))  

Output :

The original dictionary : {‘is’: {‘educational’: 4, ‘better’: 6}, ‘gfg’: {‘best’: 4, ‘good’: 5}, ‘CS’: {‘priceless’: 6}}
Dictionary after removal : {‘is’: {‘educational’: 4}, ‘gfg’: {‘best’: 4, ‘good’: 5}, ‘CS’: {}}

Method #2 : Using dictionary comprehension + isinstance() + lamda
The combination of above functionalities can be used to perform this task in one liner using lambda function.

# Python3 code to demonstrate working of  
# Remove K valued key from Nested Dictionary 
# Using dictionary comprehension + isinstance() + lamda 
  
# initializing dictionary 
test_dict = {'gfg' : {'best' : 4, 'good' : 5},  
             'is' : {'better' : 6, 'educational' : 4}, 
             'CS' : {'priceless' : 6}} 
  
# printing original dictionary 
print("The original dictionary : " + str(test_dict)) 
  
# initializing rem_val 
rem_val = 6
  
# Remove K valued key from Nested Dictionary 
# Using dictionary comprehension + isinstance() + lamda 
fnc = lambda sub: { key1: fnc(val1) if isinstance(val1, dict) else val1 
      for key1, val1 in sub.items() if val1 != rem_val} 
res = fnc(test_dict) 
  
# printing result  
print("Dictionary after removal : " + str(res))  

Output :

The original dictionary : {‘is’: {‘educational’: 4, ‘better’: 6}, ‘gfg’: {‘best’: 4, ‘good’: 5}, ‘CS’: {‘priceless’: 6}}
Dictionary after removal : {‘is’: {‘educational’: 4}, ‘gfg’: {‘best’: 4, ‘good’: 5}, ‘CS’: {}}

My Personal Notes

Python – Remove K valued key from Nested Dictionary

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