Python | Increment value in dictionary
Sometimes, while working with dictionaries, we can have a use-case in which we require to increment a particular key’s value in dictionary. It may seem a quite straight forward problem, but catch comes when the existence of a key is not known, hence becomes a 2 step process at times. Let’s discuss certain ways in which this task can be performed.
Method #1 : Using get()
The get function can be used to initialize a non-existing key with 0 and then the increment is possible. By this way the problem of non-existing key can be avoided.
# Python3 code to demonstrate working of# Increment value in dictionary# Using get() # Initialize dictionarytest_dict = {'gfg' : 1, 'is' : 2, 'for' : 4, 'CS' : 5} # printing original dictionaryprint("The original dictionary : " + str(test_dict)) # Using get()# Increment value in dictionarytest_dict['best'] = test_dict.get('best', 0) + 3 # printing result print("Dictionary after the increment of key : " + str(test_dict)) |
The original dictionary : {‘is’: 2, ‘CS’: 5, ‘for’: 4, ‘gfg’: 1}
Dictionary after the increment of key : {‘is’: 2, ‘CS’: 5, ‘for’: 4, ‘best’: 3, ‘gfg’: 1}
Method #2 : Using defaultdict()
This problem can also be solved by using a defaultdict method, which initializes the potential keys and doesn’t throw an exception in case of non-existence of keys.
# Python3 code to demonstrate working of# Increment value in dictionary# Using defaultdict()from collections import defaultdict # Initialize dictionarytest_dict = defaultdict(int) # printing original dictionaryprint("The original dictionary : " + str(dict(test_dict))) # Using defaultdict()# Increment value in dictionarytest_dict['best'] += 3 # printing result print("Dictionary after the increment of key : " + str(dict(test_dict))) |
The original dictionary : {}
Dictionary after the increment of key : {‘best’: 3}
