How to use intersec?

Hi guys, I am creating a matrix (a) from (2019, 01, 01, 01, 00, 00) to (2020, 02, 29, 24, 00, 00) with a delta = (0, 0, 0, 1, 00, 00), at the end a= 10200 x 1. In the other hand, I have another matrix (b) = 10197 x 7. In the column 7 are my values, I know there are 3 missing data. I would like to know where are the missing values so I used INTERSEC "[C, IA, IB] = intersect (fecha(a), fecha(b))". Also, when I use intersec (C, IA, IB) = 8496x1. Them I made the artificial matrix as follows:

PADPE (:,1) = fecha_s;

PADPE (:,2:7) = datevec (fecha_s); % datenum (1), Year (2), Month (3), day (4), hour (5), min (6), sec (7)

PADPE (:,8) = PADPE (:,8)= b(IA(a,1):IA(a+1,1)-1,7);

Now I would like to put the values from column (7 of b) in the column (8 of PADPE). I've been trying but I haven't got how to use it.

Thanks in advance.

[Cris LaPierre]

You haven't told us what the first 6 columns of matrix b are. You also have not told us what fecha and fecha_s are.