sciPy stats.hmean() | Python

scipy.stats.hmean(array, axis=0, dtype=None) calculates the harmonic mean of the array elements along the specified axis of the array (list in python).

It’s formula –

Parameters :
array: Input array or object having the elements to calculate the harmonic mean.
axis: Axis along which the mean is to be computed. By default axis = 0
dtype: Optional. It sets the type of returned element.

Returns : Harmonic mean of the array elements based on the set parameters.

Code #1:

# Harmonic Mean

from scipy.stats.mstats import hmean
arr1 = hmean([1, 3, 27])

print("Harmonic Mean is :", arr1)

Output:

Harmonic Mean is : 2.18918918919

Code #2: With multi-dimensional data

# Harmonic Mean

from scipy.stats.mstats import hmean
arr1 = [[1, 3, 27],
        [3, 4, 6],
        [7, 6, 3],
        [3, 6, 8]]

print("\nHarmonic Mean is :", hmean(arr1))

# using axis = 0
print("\nHarmonic Mean is with default axis = 0 : \n",
      hmean(arr1, axis = 0))

# using axis = 1
print("\nHarmonic Mean is with default axis = 1 : \n",
      hmean(arr1, axis = 1))

Output:

Harmonic Mean is : [ 2.21052632  4.36363636  6.04195804]

Harmonic Mean is with default axis = 0 : 
 [ 2.21052632  4.36363636  6.04195804]

Harmonic Mean is with default axis = 1 : 
 [ 2.18918919  4.          4.66666667  4.8       ]