How can I insert NaN value in a matrix?

Suppose I have this matrix

a = [1:6; 7:12; 13:18; 19:24]

a = 4×6

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

I want to fill the values for all the even number with NaN. How can I do it? For example, the first row of my matrix should look like:

a(1,:) = 1 NaN 3 NaN 5 NaN

Answer 1

[dpb]

a(iseven(a))=nan;           % iseven() is in Signal Processing TB

w/o the SP TB, it's not much more

a(~mod(a,2))=nan;

These are logical addressing/indexing expressions, one of the most powerful of all MATLAB syntax features. Look for and read section in the documentation on addressing matrices to learn more.