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Python | Get total keys in dictionary
  • Last Updated : 02 Aug, 2019

Sometimes, while working with Python dictionaries, one can come in a problem in which one needs to get the exact number of keys that are present in whole of dictionaries including ones that are nested. Let’s discuss certain ways in which this task can be performed.

Method #1 : Using recursion + items() + sum() + len()
This task can be performed using the combination of above functions. In this, we check if a nested is a dictionary of not and then extract it’s keys using items() and then sum of find length of it using respective functions.




# Python3 code to demonstrate working of
# Get total keys in dictionary
# Using recursion + items() + sum() + len()
  
# Utility function to perform task 
def total_keys(test_dict):
    return (0 if not isinstance(test_dict, dict
    else len(test_dict) + sum(total_keys(val) for val in test_dict.values()))
  
# Initialize dictionary
test_dict = { 'gfg' : { 'is'  : 1, 'best' : { 'for' : {'geeks' :4}}}}
  
# Printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# Using recursion + items() + sum() + len()
# Get total keys in dictionary
res = total_keys(test_dict)
  
# printing result 
print("Number of keys in dictionary is : " + str(res))
Output :

The original dictionary is : {‘gfg’: {‘best’: {‘for’: {‘geeks’: 4}}, ‘is’: 1}}
Number of keys in dictionary is : 5

 



Method #2 : Using yield() + recursion
This task can also be performed using the combination of above functions. This is just another way to perform this task. The intermediate result is returned, and hence this is a more efficient method of the 2.




# Python3 code to demonstrate working of
# Get total keys in dictionary
from collections import Mapping
  
# Utility function to perform task
def total_keys(test_dict):
     for key, value in test_dict.items():
         if isinstance(value, Mapping):
             yield from total_keys(value)
     yield len(test_dict)
  
# Initialize dictionary
test_dict = { 'gfg' : { 'is'  : 1, 'best' : { 'for' : {'geeks' :4}}}}
  
# Printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# Using yield() + recursion
# Get total keys in dictionary
res = sum(total_keys(test_dict))
  
# printing result 
print("Number of keys in dictionary is : " + str(res))
Output :

The original dictionary is : {‘gfg’: {‘best’: {‘for’: {‘geeks’: 4}}, ‘is’: 1}}
Number of keys in dictionary is : 5

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