How to index one array with the index of another array that meets a certain condition

I have two arrays that correspond to variables of a cloud. One is cloud type and the other is effective radius of the cloud droplet.

I want to find the indexes in the cloud type array where cloud type == 8 and then index my cloud droplet radius array to only show the values in the specific index where cloud type == 8. Can anyone help with this?

ex:

cloud_type = [0 0 6 8 8 5 1 8 2 2 8]

radius = [20 13 14 25 30 10 5 27 13 14 25]

out = [25 30 27 25]

Answer 1

[Star Strider]

Try this:

cloud_type = [0 0 6 8 8 5 1 8 2 2 8];
radius = [20 13 14 25 30 10 5 27 13 14 25];

out = radius(cloud_type==8)

producing:

out =
    25    30    27    25

[Kyle Vanlerberghe]

Didn't think it was this simple. Thank you so much!

[Star Strider]

As always, my pleasure!

This code uses ‘logical indexing’. See: Matrix Indexing for details.