how to vector with the same length of matrix

Hi everyone,

I have to do a vector with the same lenght of matrix. This new vector should contain a package of hour from 1 to 8766, one time that it arrives to end point (8766) it must restarts from 1 and arrives to 8766 and this for the all length of the matrix. I hope to have been clear enough. Thank you.

File = 'D:\Valerio\data\Time_dir_Analysis\Analisys\data\a_ERA5.xlsx';
readFile = xlsread(File);
ERA5 = unique(readFile,'rows');

dt_ERA5 = datetime([ERA5(:,1:4) repmat([0 0],size(ERA5,1),1)]);
tt_ERA5 = timetable(dt_ERA5,ERA5(:,5:end));

[Eva-Maria Weiss]

I'm not sure, if I got the point. The problem is that size of Matrix is not devisible by 8766?

Maybe the mod function would help b = mod(a,m). Then you can create first your vector by means of repmat function as much as it 'fits'

(floor(size(Matrix,1)/8766)) 

into the matrix size and then concatenate the 'rest' as 1:b...

Answer 1

[Ameer Hamza]

Try something like this

n = size(ERA5,1);
hours_vector = mod((1:n)-1,8766)+1;

hours_vector is like this

hours_vector = [1 2 3 .. .. 8765 8766 1 2 3 .. .. 8765 8766 ..]

Answer 2

[Peter Perkins]

I'm going to suggest that you stay away from xlsread, and use readtable instead. Putting that together with Am eer's answer, you have

ERA5 = readtable('a_ERA5.xlsx');
ERA5.Time = datetime(ERA5{:,1:3}) + hours(ERA5.Var4);
ERA5 = table2timetable(ERA5(:,5:end));

n = height(ERA5);
ERA5.Hours = hours(mod((1:n)-1,8766)+1)';
head(ERA5)
ans =
  8×6 timetable
            Time            Var5     Var6      Var7      Var8      Var9     Hours
    ____________________    _____    _____    ______    ______    ______    _____
    01-Jan-2005 00:00:00    0.652    8.216    66.211     1.371    -1.466    1 hr 
    01-Jan-2005 01:00:00    0.645    8.029    65.466     0.559     -2.62    2 hr 
    01-Jan-2005 02:00:00    0.635    7.915    64.978    -0.359    -3.037    3 hr 
    01-Jan-2005 03:00:00    0.622     7.81    64.896    -0.861    -2.831    4 hr 
    01-Jan-2005 04:00:00    0.608    7.702    64.785     -0.94    -2.648    5 hr 
    01-Jan-2005 05:00:00    0.594    7.593    64.776    -1.396    -2.675    6 hr 
    01-Jan-2005 06:00:00    0.582    7.484    64.675    -1.944    -2.773    7 hr 
    01-Jan-2005 07:00:00    0.569    7.369    64.665    -2.103    -2.613    8 hr 

I don't actually understand what you want to do with the vector of "hours", but perhaps something like that.