Method 4 : Using the built-in map() function and lambda function
Step-by-step approach:
- Define a lambda function that takes a key-value pair from a dictionary as an argument and returns a tuple with the key and the modified value (reinitialized to K if it’s a list).
- Use the map() function to apply the lambda function to each key-value pair in the dictionary and create a new dictionary with the modified values.
- Return the new dictionary.
Python3
def reinitialize_dict(d, K): return dict(map(lambda item: (item[0], [K]*len(item[1]) if isinstance(item[1], list) else K), d.items()))# initializing dictionarytest_dict = {'gfg': [4, 6, 7], 'is': 8, 'best': [[4, 5], [8, 9, 20]]}# printing original dictionaryprint("The original dictionary : " + str(test_dict))# initializing K K = 4# Reinitialize Value lists to K in Dictionaryres = reinitialize_dict(test_dict, K)# printing result print("The Reinitialized dictionary : " + str(res)) |
Output
The original dictionary : {'gfg': [4, 6, 7], 'is': 8, 'best': [[4, 5], [8, 9, 20]]}
The Reinitialized dictionary : {'gfg': [4, 4, 4], 'is': 4, 'best': [4, 4]}
Time complexity: O(n), where n is the number of key-value pairs in the dictionary.
Auxiliary space: O(n), for the new dictionary.
Python – Reinitialize Value lists to K in Dictionary
Sometimes, while working with Python dictionary values, we can have a problem in which we need to reinitialize all the values lists of all keys in dictionary to a constant K. This kind of problem can have application in domains which use data, like Machine Learning and Data Science. Let’s discuss certain way in which this task can be performed.
Input : test_dict = {‘Gfg’ : [[4, 5], [8, 9, 20], [1, 3, 4, ‘oops’]]}
Output : {‘Gfg’: [[4, 4], [4, 4, 4], [4, 4, 4, 4]]}Input : test_dict = {‘Gfg’ : “best”}
Output : {‘Gfg’ : 4}