How to sum values of a Python dictionary?

It is pretty easy to get the sum of values of a Python dictionary. You can first get the values in a list using the dict.values(). Then you can call the sum method to get the sum of these values.

Example

Here's how to sum dictionary values using the sum() function ?

d = {
    'foo': 10,
    'bar': 20,
    'baz': 30
}
print(sum(d.values()))

This will give the output ?

60

Using List Comprehension

You can also sum dictionary values using list comprehension ?

scores = {'Alice': 85, 'Bob': 92, 'Charlie': 78}
total = sum([value for value in scores.values()])
print(total)

255

Summing Based on Conditions

To sum only values that meet certain criteria ?

prices = {'apple': 2.5, 'banana': 1.2, 'orange': 3.0, 'grape': 4.5}

# Sum only prices greater than 2
expensive_total = sum(price for price in prices.values() if price > 2)
print(f"Total for expensive items: ${expensive_total}")

Total for expensive items: $10.0

Handling Mixed Data Types

When dictionary contains non-numeric values, filter them first ?

mixed_data = {'count': 15, 'name': 'John', 'score': 88, 'active': True}

# Sum only numeric values
numeric_sum = sum(value for value in mixed_data.values() if isinstance(value, (int, float)))
print(f"Sum of numeric values: {numeric_sum}")

Sum of numeric values: 103

Conclusion

Use sum(dict.values()) for simple dictionary value summation. For conditional summation, combine sum() with generator expressions or list comprehension.