Given a dictionary and a Key, add new item after a particular key in dictionary.
Input : test_dict = {“Gfg” : 3, “is” : 5, “for” : 8, “Geeks” : 10}, K = “is”, add_item = {“good” : 19}
Output : {‘Gfg’: 3, ‘is’: 5, ‘good’: 19, ‘for’: 8, ‘Geeks’: 10}
Explanation : Item added after desired key in dictionary.Input : test_dict = {“Gfg” : 3, “is” : 5, “for” : 8, “Geeks” : 10}, K = “for”, add_item = {“good” : 19}
Output : {‘Gfg’: 3, ‘is’: 5, ‘for’: 8, ‘good’: 19, ‘Geeks’: 10}
Explanation : Item added after desired key in dictionary.
Method 1: Using loop + update()
In this we iterate for all the keys, and when target key is encountered, the iteration is halted and dictionary is updated with required key. Then iteration is resumed.
Python3
# Python3 code to demonstrate working of # Dictionary Keys whose Values summation equals K # Using loop + update()# initializing dictionarytest_dict = {"Gfg" : 3, "is" : 5, "for" : 8, "Geeks" : 10}# printing original dictionaryprint("The original dictionary is : " + str(test_dict))# initializing K K = "is"# initializing dictionary to be added add_item = {"best" : 19}# using dictionary comprehension res = dict()for key in test_dict: res[key] = test_dict[key] # modify after adding K key if key == K: res.update(add_item)# printing result print("Modified dictionary : " + str(res)) |
The original dictionary is : {'Gfg': 3, 'is': 5, 'for': 8, 'Geeks': 10}
Modified dictionary : {'Gfg': 3, 'is': 5, 'best': 19, 'for': 8, 'Geeks': 10}
Time Complexity: O(n), where n is the values in dictionary
Auxiliary Space: O(n), where n is the size of dictionary
Method 2: Using keys(),values(),items(),insert(),index() methods
Approach
- Access the keys and values of test_dict using keys(),values()methods
- Insert the new key into keys list and value into values list after K using insert(),index() method
- Now create a new dictionary using keys list and values list by for loop
- Display the new dictionary
Python3
# Python3 code to demonstrate working of# Dictionary Keys whose Values summation equals K# initializing dictionarytest_dict = {"Gfg" : 3, "is" : 5, "for" : 8, "Geeks" : 10}# printing original dictionaryprint("The original dictionary is : " + str(test_dict))# initializing KK = "is"# initializing dictionary to be addedadd_item = {"best" : 19}res=dict()a=list(add_item.items())x=list(test_dict.keys())y=list(test_dict.values())x.insert(x.index(K)+1,a[0][0])y.insert(x.index(K)+1,a[0][1])for i in range(0,len(x)): res[x[i]]=y[i]# printing resultprint("Modified dictionary : " + str(res)) |
The original dictionary is : {'Gfg': 3, 'is': 5, 'for': 8, 'Geeks': 10}
Modified dictionary : {'Gfg': 3, 'is': 5, 'best': 19, 'for': 8, 'Geeks': 10}
Time Complexity : O(N)
Auxiliary Space : O(N)
Method 3: Using dictionary comprehension and the get() method
- Initialize the dictionary test_dict and the key K with their respective values.
- Initialize the dictionary add_item with the key-value pair that needs to be added to the test_dict.
- Calculate the sum of all values in the dictionary using the sum() method.
- Check if the sum of all values is equal to K or not.
- If the sum is equal to K, return the original dictionary as the result.
- If the sum is not equal to K, add the new key-value pair to the dictionary and return the modified dictionary as the result.
Python3
# Python3 code to demonstrate working of# Dictionary Keys whose Values summation equals K# Using dictionary comprehension and get()# initializing dictionarytest_dict = {"Gfg" : 3, "is" : 5, "for" : 8, "Geeks" : 10}# printing original dictionaryprint("The original dictionary is : " + str(test_dict))# initializing KK = 18# initializing dictionary to be addedadd_item = {"best" : 19}# calculate the sum of all values in the dictionarysum_values = sum(test_dict.values())# check if the sum of all values is equal to K or notif sum_values == K: res = test_dictelse: # add the new key-value pair to the dictionary test_dict.update(add_item) # return the modified dictionary res = test_dict# printing resultprint("Modified dictionary : " + str(res)) |
The original dictionary is : {'Gfg': 3, 'is': 5, 'for': 8, 'Geeks': 10}
Modified dictionary : {'Gfg': 3, 'is': 5, 'for': 8, 'Geeks': 10, 'best': 19}
Time complexity: O(n), where n is the number of elements in the dictionary.
Auxiliary space: O(1), as we are not using any extra space for computation.
