Python how to sum all the numbers in a dictionary

Question

I’m new to python and having problems with summing up the numbers inside an element and then adding them together to get a total value.

Example of what I’m trying to do:

list = {'area1': [395.0, 212.0], 'area2': [165.0, 110.0]}

'area1': [395.0 * 212.0], 'area2': [165.0 * 110.0]

'area1': [83740], 'area2': [18150]

total value = 101890

Main.py:

def cubicMeterCalculator():
    floorAreaList = {}
    
    print("Example of how this would look like 'area1 395 212' 'area2 165 110'")
    n = int(input("nHow many walls? "))
    
    for i in range(n):
        print("nEnter name of the wall first and 'Space' to separate the name and numbers before hitting enter.")
        name, *lengths = input().split(" ")
        l_lengths = list(map(float,lengths))
        floorAreaList[name] = l_lengths
    
    print(floorAreaList)
    
    total = sum(float, floorAreaList)
    print(total)

Asked By: Snickers

||

Source

Answer 1

You can use a generator expression to multiply the pairs of values in your dictionary, then sum the output of that:

lst = {'area1': [395.0, 212.0], 'area2': [165.0, 110.0]}
total = sum(v[0]*v[1] for v in lst.values())
# 101890.0

Answered By: Nick

Answer 2

You can find the area using list comprehension.

Iterate through lst.values() -> dict_values([[395.0, 212.0], [165.0, 110.0]]) and multiply the elements. Finally, use sum to find out the total.

lst = {'area1': [395.0, 212.0], 'area2': [165.0, 110.0]}

area = sum([i[0]*i[1] for i in lst.values()])
# 101890.0

As solution with map + sum,

sum(map(lambda x: x[0]*x[1], lst.values()))

Answered By: Rahul K P

Answer 3

The answer with sum, map, and a lambda is probally the best for just areas.

Give this a try if there are more dimensions:

this approach scales with dimensions collected (areas and volumes). We can use the reduce function with a lambda expression to handle multidimensional situations (i.e. you collect LxWxH and want the sum of the volumes)

from functools import reduce

inputs = {'area1': [395.0, 212.0], 'area2': [165.0, 110.0]}

vals = [reduce(lambda x, y: x*y,p) for p in inputs.values()]
total = sum(vals)
print(total)

with more dimensions

inputs = {'vol1': [395.0, 212.0, 10.0], 'vol2': [165.0, 110.0, 10.0]}

vals = [reduce(lambda x, y: x*y,p) for p in inputs.values()]
total = sum(vals)
print(total)

Answered By: Skyehawk

Answer 4

I think something like this will do the trick

from functools import reduce
total = sum([reduce(lambda x, y: x*y, area) for area in floorAreaList.values()])

with values() you get the values of the dictionary and then with the lambda you multiply every element and in the end sum them.

Answered By: Dimitrios Mavrommatis

Python how to sum all the numbers in a dictionary

Question:

Answers: