Given a dictionary, update its every key by adding a prefix to each key.
Input : test_dict = {‘Gfg’ : 6, ‘is’ : 7, ‘best’ : 9}, temp = “Pro” Output : {‘ProGfg’ : 6, ‘Prois’ : 7, ‘Probest’ : 9} Explanation : “Pro” prefix added to each key. Input : test_dict = {‘Gfg’ : 6, ‘is’ : 7, ‘best’ : 9}, temp = “a” Output : {‘aGfg’ : 6, ‘ais’ : 7, ‘abest’ : 9} Explanation : “a” prefix added to each key.
Method #1: Using dictionary comprehension
This is one of the methods by which this task can be performed. In this, we construct a new dictionary by performing the concatenation of prefixes with all keys.
Python3
# Python3 code to demonstrate working of # Add prefix to each key name in dictionary# Using loop# initializing dictionarytest_dict = {'Gfg' : 6, 'is' : 7, 'best' : 9, 'for' : 8, 'Lazyroar' : 11} # printing original dictionaryprint("The original dictionary is : " + str(test_dict))# initializing prefix temp = "Pro"# + operator is used to perform task of concatenationres = {temp + str(key): val for key, val in test_dict.items()}# printing result print("The extracted dictionary : " + str(res)) |
The original dictionary is : {'Gfg': 6, 'is': 7, 'best': 9, 'for': 8, 'Lazyroar': 11}
The extracted dictionary : {'ProGfg': 6, 'Prois': 7, 'Probest': 9, 'Profor': 8, 'ProLazyroar': 11}
Method #2 : Using f strings + dictionary comprehension
The combination of the above functionalities can be used to solve this problem. In this, we perform the task of concatenation using f strings. Works only in >=3.6 versions of Python.
Python3
# Python3 code to demonstrate working of # Add prefix to each key name in dictionary# Using f strings + dictionary comprehension# initializing dictionarytest_dict = {'Gfg' : 6, 'is' : 7, 'best' : 9, 'for' : 8, 'Lazyroar' : 11} # printing original dictionaryprint("The original dictionary is : " + str(test_dict))# initializing prefix temp = "Pro"# dictionary comprehension is used to bind result # f strings are used to bind prefix with keyres = {f"Pro{key}": val for key, val in test_dict.items()}# printing result print("The extracted dictionary : " + str(res)) |
The original dictionary is : {'Gfg': 6, 'is': 7, 'best': 9, 'for': 8, 'Lazyroar': 11}
The extracted dictionary : {'ProGfg': 6, 'Prois': 7, 'Probest': 9, 'Profor': 8, 'ProLazyroar': 11}
Method #3: Using dictionary comprehension with the zip() function
The zip() function creates tuples of the new keys and the values, and then converts the tuples back into a dictionary.
Step-by-Step Algorithm:
- Initialize the input dictionary.
- Initialize the prefix string.
- Using dictionary comprehension and zip(), create a list of tuples containing new keys with the prefix and old values.
- Convert the list of tuples to a dictionary.
- Print the extracted dictionary.
Python3
# initializing dictionarytest_dict = {'Gfg' : 6, 'is' : 7, 'best' : 9, 'for' : 8, 'Lazyroar' : 11} # printing original dictionaryprint("The original dictionary is : " + str(test_dict))# initializing prefix temp = "Pro"# using dictionary comprehension with zip() to create tuples of new keys and valuesres = dict(zip([temp+key for key in test_dict.keys()], test_dict.values()))# printing result print("The extracted dictionary : " + str(res)) |
The original dictionary is : {'Gfg': 6, 'is': 7, 'best': 9, 'for': 8, 'Lazyroar': 11}
The extracted dictionary : {'ProGfg': 6, 'Prois': 7, 'Probest': 9, 'Profor': 8, 'ProLazyroar': 11}
Complexity Analysis :
Time Complexity: O(n), where n is the number of elements in the dictionary. The dictionary comprehension operation is O(n), and the zip operation is also O(n).
Space Complexity: O(n), where n is the number of elements in the dictionary. The space required is for the dictionary res that stores the new keys and values.
