CODEWITHSUNDEEP
pythonloopsnumpysum
dominoslater
dominoslater

Reputation: 21

Sum a list of results in Python

I have a loop running in Python, but want to sum the results. Here's my code:

R=0.05
Timestep = np.array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
Cash_flow = np.array([-10000, 300, 1000, 2500, 6000, 6100, 6250, 6250, 6300, 6300, 6200])

for i in Timestep:
    Present_value = Cash_flow[i]*(1+R)**-(Timestep[i])
    print(Present_value)

And here are the results:

    -10000.0
285.714285714
907.029478458
2159.59399633
4936.21484875
4779.50961546
4663.84622898
4441.75831331
4264.08798078
4061.03617217
3806.26217195

I would like to make sum these values; is there a simple way of doing so?

Cheers!

Upvotes: 0

Views: 112

Answers (2)

Jean-François Fabre
Jean-François Fabre

Reputation: 140168

avoid the loop & use vector capability of numpy

sum_of_values = np.sum(Cash_flow[:]*(1+R)**-(Timestep[:]))
print(sum_of_values)

(sum would also work instead of numpy.sum)

results in:

24305.0530919

yields the same as the "classical" way, only faster and without loop:

sum_of_values=0
for i in Timestep:
    sum_of_values += Cash_flow[i]*(1+R)**-(Timestep[i])

Upvotes: 2

Rok Povsic
Rok Povsic

Reputation: 4925

You can simply add my_sum = 0 before the for loop and my_sum += Preset_value inside for loop after you set Preset_value.

At the end of the program (outside of for loop), you can print it with print(my_sum)

Upvotes: 0

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