Finding the mean of Python list

user_11643215 0
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I am trying to find the mean of a Python list. When I print my list it is as follows:

[array([0.33345667, 0.33523274, 0.33222637, 0.3341597 , 0.33329942,
       0.3330034 , 0.33197044, 0.33394078, 0.33458831, 0.33147091])]

That outcome is expected, there are no null values.

When I try statistics.mean(accuracy_list) (which is what I have done in the past to get the mean) I get this error

TypeError: can't convert type 'ndarray' to numerator/denominator

Any ideas?

mean dataframe list python
3 Answers

statistics.mean() works on vanilla Python lists. It does not work on numpy.ndarrays. You should use numpy.mean() instead.

Also, it looks like accuracy_list is a list containing a one-element numpy list. If that is the case, you can use list unpacking:

import numpy as np
[accuracy_list] = [np.array([0.33345667, 0.33523274, 0.33222637, 0.3341597 , 0.33329942,
       0.3330034 , 0.33197044, 0.33394078, 0.33458831, 0.33147091])]

np.mean(accuracy_list)

Both of these output:

0.333334874
user_177698150

I'm not sure why there's a NumPy array in the list, so you could just extract it and compute the mean:

accuracy_list[0].mean()
user_43544770

Try this:

l = [15, 18, 2, 36, 12, 78, 5, 6, 9]

import statistics
statistics.mean(l)

OR

On older versions of Python you can do:

sum(l) / len(l)

On Python 2, you need to convert len to a float to get float division:

sum(l) / float(len(l))
user_143769030
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