CODEWITHSUNDEEP
pythonarraysnumpy
Nicole
Nicole

Reputation: 49

return array containing average of each of the specified columns

I've been going crazy trying to find a way out.

Input a 2D array and several column numbers, return the average of every number in those specific columns in the form of array.

I know how to output the average of all columns, but I have no idea how to output only specific columns' averages.

a = array([[0, 0,1], [1, 1,2], [3, 3,3]])

get_average(a,[0,1])

array([1.333333333, 1.333333333333])

Upvotes: 0

Views: 72

Answers (1)

John1024
John1024

Reputation: 113814

Averaging in numpy

numpy has an average function:

>>> import numpy as np
>>> a = np.array([[0, 0,1], [1, 1,2], [3, 3,3]])
>>> np.average(a[:,(0,1)], axis=0)
array([ 1.33,  1.33])

For np.average, axis specifies the array axis along with to average. axis=0, for example, averages over the rows.

np.average also offers weighted averages if you ever need them.

Defining a get_average function

If you think you still want a get_average function, then:

def get_average(a, cols):
    return np.average(a[:,cols], axis=0)

Upvotes: 1

Related Questions