MATLAB Answers

Sharah
0

How to get first value of an array with condition

Asked by Sharah
on 11 Jul 2018
Latest activity Edited by Adam Danz
on 11 Jul 2018
I need to get the first value of a matrix (x2 below) that I initially put condition to, for example:
x1 = Data{i}.Error(something == 1, 1)
x2 = x1(1)
I need to do this within one step without creating `x1', is it possible? Obviously
Data{i}.Error(something == 1, 1)(1)
won't work

  0 Comments

Sign in to comment.

1 Answer

Answer by Adam Danz
on 11 Jul 2018
Edited by Adam Danz
on 11 Jul 2018
 Accepted Answer

By using the 2nd input to find() you can get just the first index of 'Error'.
% fake data
Data{1}.Error = magic(10);
something = [0 1 0 1 0 1 0 0 0 0];
% 2-line method
x1 = Data{1}.Error(something == 1, 1);
x2 = x1(1);
% 1-line method
x3 = Data{1}.Error(find(something == 1, 1), 1);
% Check that they match
x2 == x3
Note that this works if x2 is always the first element of x1. If you're looking for the n_th element of x1 you'll need to replace find() with
max(find(something == 1), n).

  0 Comments

Sign in to comment.