fill ids numbers in the matrix

Hi,

I am trying to refill excell matrix with trial ids numbers and would like to ask if there are easy way to do it in matlab

I have matrices of 4 columns that log stimuli representation in time (logfile, attached below ). The rows are time and the columns are events. The first column logs stimuli id in time. (No stimulus =0, stimulus : 1 2 3 4 5 or 6) The second column logs the trial stages(1=pre stimulus, 2=stimulus, 3=poststimulus interval); column 4 logs Id of repetition for 6 stimuli.

I need to write in column3 Ids numbers of each trial (pre + stimulus + post) through the length of each trial as in example-logfile (column 3). Files are attached below. For example, first trial in the logfile (column2) is 158 rows (pre + stim +post interval). I need to fill correspondent 158 rows in column 3 with 1 which is ID of the first trial. Next trial with 2 and so on as in an example-logfile (column 3). Could anyone help with this?

Answer 1

[Star Strider]

I had to plot ‘example-logfile’ to figure out how it works.

Try this —

TLf = readtable('Logfile.xlsx');
TLf.Var3 = cumsum(diff([0; TLf.Var2])<0)+1

TLf = 4760×4 table
    Var1    Var2    Var3    Var4
    ____    ____    ____    ____

     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  
     0       1       1       1  

TLf(end-9:end,:)

ans = 10×4 table
    Var1    Var2    Var3    Var4
    ____    ____    ____    ____

     0       3       30      5  
     0       3       30      5  
     0       3       30      5  
     0       3       30      5  
     0       3       30      5  
     0       3       30      5  
     0       3       30      5  
     0       3       30      5  
     0       3       30      5  
     0       3       30      5  

EDIT — (29 Apr 2023 at 15:26)

It is straightforward to count the ends of the trials and then add them to get ‘Var3’.

.

[EK]

Thanks it works!

[Star Strider]

As always, my pleasure!