Python program to find the sum of all items in a dictionary

Given a dictionary in Python, write a Python program to find the sum of all items in the dictionary.

Examples:

Input : {‘a’: 100, ‘b’:200, ‘c’:300}
Output : 600

Input : {‘x’: 25, ‘y’:18, ‘z’:45}
Output : 88

Using Inbuilt sum() Function

Use the sum function to find the sum of dictionary values.

Python3

# Python3 Program to find sum of
# all items in a Dictionary

# Function to print sum


def returnSum(myDict):

    list = []
    for i in myDict:
        list.append(myDict[i])
    final = sum(list)

    return final


# Driver Function
dict = {'a': 100, 'b': 200, 'c': 300}
print("Sum :", returnSum(dict))

Output:

Sum : 600

Using For loop to iterate through values using values() function

Iterate through each value of the dictionary using values() function and keep adding it to the sum.

Python3

# Python3 Program to find sum of
# all items in a Dictionary

# Function to print sum


def returnSum(dict):

    sum = 0
    for i in dict.values():
        sum = sum + i

    return sum


# Driver Function
dict = {'a': 100, 'b': 200, 'c': 300}
print("Sum :", returnSum(dict))

Output:

Sum : 600

Using for loop to iterate over each value in a dictionary

Iterate through each item of the dictionary and simply keep adding the values to the sum variable. 

Python3

# Python3 Program to find sum of
# all items in a Dictionary

# Function to print sum


def returnSum(dict):

    sum = 0
    for i in dict:
        sum = sum + dict[i]

    return sum


# Driver Function
dict = {'a': 100, 'b': 200, 'c': 300}
print("Sum :", returnSum(dict))

Output:

Sum : 600

Using values() and sum() function

Here we are using the dictionary.sum() method to find the sum of values taken out through dictionary.values() function

Python3

# Python3 Program to find sum of
# all items in a Dictionary

# Function to print sum


def returnSum(dict):
    return sum(dict.values())


# Driver Function
dict = {'a': 100, 'b': 200, 'c': 300}
print("Sum :", returnSum(dict))

Output:

Sum : 600

Using the lambda function

The lambda function is used to calculate the summation of all the values in the dictionary 

Python3

import functools

dic = {'a': 100, 'b': 200, 'c': 300}

sum_dic = functools.reduce(lambda ac,k: ac+dic[k], dic, 0)

print("Sum :", sum_dic)

Output:

Sum : 600

Using a generator expression and the built-in sum function

Another approach to find the sum of all items in a dictionary is to use a generator expression and the built-in sum function. A generator expression is an expression that generates a sequence of values, and is similar to a list comprehension, but does not create a new list.

For example:

Python3

def returnSum(myDict):
    return sum(myDict[key] for key in myDict)

dict = {'a': 100, 'b': 200, 'c': 300}
print("Sum :", returnSum(dict))

#This code is contributed by Edula Vinay Kumar Reddy

Output

Sum : 600

This approach has a time complexity of O(n), where n is the number of items in the dictionary, since it involves iterating through the dictionary to generate the sequence of values. The space complexity is also O(n), since it generates a sequence of values that is the same size as the original dictionary.