Python - How to divide numbers in list of lists?

Question

Hi i have been trying to get the mean of each sub-list using sum/length.

vectors = [[2.731018, 1.7550012, 2.3455532],
 [2.9210236, 3.2172325],
 [2.9255183, 2.66712, 2.7174947]]  

mean_vec = [sum(i)/len(i) for i in vectors]

Currently i am using the code above, however i am being prompted with this error message:

ZeroDivisionError: division by zero

The list above is just a sample. i have a much larger list of numbers. please advice me on how i should solve this

Your code works fine for me. You must have an empty list somewhere in your real dataset. — Loocid, Oct 10 '18 at 01:40
alright problem solved hehe. my apologies for not checking properly. :P — Cua, Oct 10 '18 at 01:49

score 2 · Accepted Answer · edited Oct 10 '18 at 02:01

2

Your provided code mean_vec = [sum(i)/len(i) for i in vectors] can fail in certain scenarios

[] #an empty list

Please add len(i) != 0 in your code as show below

mean_vec = [sum(i)/len(i) for i in vectors if len(i) != 0]

edited Oct 10 '18 at 02:01

slider

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answered Oct 10 '18 at 01:51

Shivam Seth

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Python - How to divide numbers in list of lists?

1 Answers1