Numpy: Get minimum value indices in array, ignoring specific value

Question

I'm trying to get the indices of the minimum values in array, such as:

ind = np.where((arr == arr.min()))

I'd like to modify this so that I can ignore a specific value. e.g:

ind = np.where((arr == arr[arr != value].min()))

The above solution is ok, but can it be done better?

meaning faster? or less memory use? ... What size are your arrays? — usethedeathstar
– usethedeathstar, Commented Mar 21, 2014 at 13:08

Saullo G. P. Castro · Accepted Answer · 2014-03-23 12:21:39Z

3

You can create a masked array and then use np.where() on it:

m = np.ma.masked_array(a, mask=(a==value))
np.where(m, m==m.min())

giving what you want.

answered Mar 23, 2014 at 12:21

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Comments

Raphael Roth · Accepted Answer · 2014-03-21 12:09:42Z

2

use numpys argmin()

ind= np.argmin(arr[arr!=value])

answered Mar 21, 2014 at 12:09

Raphael Roth

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argmin returns only the first index.