How to replace elements of a numpy array from two different arrays-CodePudding

For an array

array2 = np.array([np.nan, np.nan, np.nan, np.nan, 45, np.nan, 33, np.nan,
               np.nan, 32, np.nan, np.nan, 44, np.nan, 10, 53, np.nan])

I need to replace elements consequently by condition: if an element is less than np.mean(array2), it should be taken from ordered_array_1 = [32, 10, 33], otherwise - from ordered_array_2 = [44, 53, 45].

I haven't managed to use np.putmask, or numpy.where for that purpose, as for example np.putmask(array2[~np.isnan(array2)],mask,ordered1) doesn't replace elements at all. The array2 doesn't change.

I expect this result after replacement from both arrays:

array2 = np.array([np.nan, np.nan, np.nan, np.nan, 44, np.nan, 32, np.nan,
                   np.nan, 10, np.nan, np.nan, 53, np.nan, 33, 45, np.nan])

CodePudding user response：

Use np.where np.nanmean as follows:

import numpy as np

array2 = np.array([np.nan, np.nan, np.nan, np.nan, 45, np.nan, 33, np.nan,
                   np.nan, 32, np.nan, np.nan, 44, np.nan, 10, 53, np.nan])

ordered_array_1 = [32, 10, 33]
ordered_array_2 = [44, 53, 45]

array2[np.where(array2 < np.nanmean(array2))] = ordered_array_1
array2[np.where(array2 >= np.nanmean(array2))] = ordered_array_2

print(array2)

Output

[nan nan nan nan 44. nan 32. nan nan 10. nan nan 53. nan 33. 45. nan]