Python Program to print sum of all key value pairs in a Dictionary

Given a dictionary arr consisting of N items, where key and value are both of integer type, the task is to find the sum of all key value pairs in the dictionary.

Examples:

Input: arr = {1: 10, 2: 20, 3: 30}
Output: 11 22 33
Explanation:
Sum of key and value of the first item in the dictionary = 1 + 10 = 11.
Sum of key and value of the second item in the dictionary = 2 + 20 = 22.
Sum of key and value of the third item in the dictionary = 3 + 30 = 33.

Input: arr = {10 : -5, 5 : -10, 100 : -50}
Output: 5 -5 50

Method 1:

Approach using dictionary traversal technique: The idea is to traverse through the keys of dictionary using for loop. Follow the steps below to solve the problem:

• Initialize a list, say l, to store the result.
• Traverse the dictionary arr and then append i + arr[i] into the list l.
• After completing the above steps, print the list l as the required answer.

Below is the implementation of the above approach:

Python3

# Python3 implementation of
# the above approach

# Function to print the list containing
# the sum of key and value pairs of
# each item of a dictionary


def FindSum(arr):

    # Stores the list containing the
    # sum of keys and values of each item
    l = []

    # Traverse the dictionary
    for i in arr:

        l.append(i + arr[i])

    # Print the list l
    print(*l)

# Driver Code


arr = {1: 10, 2: 20, 3: 30}

FindSum(arr)

Output

11 22 33

Time Complexity: O(N)
Auxiliary Space: O(N)

Method 2:

Approach using keys() Method: An alternate approach to solve the problem is to use keys() method. Follow the steps below to solve the problem:

• Initialize a list, say l, to store the result.
• Traverse through the list of keys of dictionary arr and then append.
• After completing the above steps print the list l as answer.

Below is the implementation of the above approach:

Python3

# Python3 implementation of the above approach

# Function to print the list
# containing the sum of key and
# value pairs from a dictionary


def FindSum(arr):

    # Stores the list containing the
    # sum of keys and values of each item
    l = []

    # Traverse the list of keys of arr
    for i in arr.keys():

        l.append(i + arr[i])

    # Print the list l
    print(*l)

# Driver Code


arr = {1: 10, 2: 20, 3: 30}

FindSum(arr)

Output

11 22 33

Time Complexity: O(N)
Auxiliary Space: O(N)

Method 3 : Using keys(),values() and for loop

Python3

# Python3 implementation of the above approach
arr = {1: 10, 2: 20, 3: 30}
x = list(arr.keys())
y = list(arr.values())
res = []
for i in range(0, len(x)):
    res.append(x[i]+y[i])
for i in res:
    print(i, end=" ")

Output

11 22 33 

Time Complexity: O(n), where n is the number of keys in the dictionary.
Auxiliary Space: O(n), as two arrays of size n are created to store the keys and values of the dictionary.

Method 4: Using zip() and a list comprehension

This approach uses the python built-in function zip() to extract the keys and values of the dictionary and combines them in a tuple. Using a list comprehension, we add the key and value of each item in the dictionary. The final result is the sum of all key-value pairs in the dictionary. The time complexity of this approach is O(n) and the space complexity is O(n) as we are creating a new list to store the sum of each key-value pair.

Python3

def find_sum(arr):
    # Using zip to get the keys and values of the dictionary
    keys, values = zip(*arr.items())
    # Using list comprehension to add the key and value of each item
    return [k+v for k,v in zip(keys, values)]

arr = {1: 10, 2: 20, 3: 30}
print(find_sum(arr))
#This code is contributed by Edula Vinay Kumar Reddy

Output

[11, 22, 33]

Time Complexity: O(n)
Auxiliary Space: O(n)

Method 5: Using a simple for loop to iterate over the keys and values of the dictionary

Directly iterate over the items of the dictionary using the items() method, which returns a sequence of (key, value) pairs. We then add each key and value together and append the result to a list. Finally, we return the list of results.

Python3

def find_sum(arr):
    # Create an empty list to store the result
    result = []

    # Iterate over the keys and values of the dictionary
    for key, value in arr.items():
        # Add the key and value and append the result to the list
        result.append(key + value)

    # Return the list of results
    return result

# Example usage:
arr = {1: 10, 2: 20, 3: 30}
print(find_sum(arr))
# Output: [11, 22, 33]

Output

[11, 22, 33]

Time complexity: O(n), where n is the number of items in the dictionary.
Auxiliary space: O(n), since we are creating a list to store the result.

Method 6:Using itertools strmap()

Algorithm:

1. Import the itertools.starmap() function
2. Define the find_sum() function that takes a dictionary arr as input
3. Use the starmap() function with a lambda function to add the key and value of each item in the dictionary arr
4. Convert the resulting iterable of sums to a list and return the list

Python3

from itertools import starmap

def find_sum(arr):
    return list(starmap(lambda key, value: key+value, arr.items()))

# example usage
arr = {1: 10, 2: 20, 3: 30}
result = find_sum(arr)
print(result)  # Output: [11, 22, 33]
#This code is contributed by Vinay pinjala.

Output

[11, 22, 33]

Time complexity:
The time complexity of the find_sum() function is O(n), where n is the number of items in the dictionary arr. The starmap() function iterates over each item in the dictionary and applies a lambda function to calculate the sum of the key and value for each item. The time complexity of the lambda function is constant, so it does not affect the overall time complexity of the function.

Auxiliary Space:

Auxiliary Space of the code is O(1),because we don’t storing list.