Create new columns in tale adding prior data

I have a table (sample attached) summarising neural activity; either 1 or -1. The rest are blanks. The first two columns relate to the test. The third column onwards is a summary of the activity. There are 68 of these columns. These 68 regions are part of larger regions denoted by first part of text within each column (LF, LC, LT etc). The number of columns per region differs. I want to create a new series of columns that adds the aboslute value of these sub regions so I'll have columns with the value of the overall region ie LF_1... = 1, LF_2... = -1, LF_3... = 1 Resulting column LF will be 3 for that row. How can I do this? Is there a way to automatically recognise the first letters prior to the first "_" to create a new column?

Answer 1

[Cris LaPierre]

Columns in a table are variables. Here, you want to just create a 'new' variable, and set it equal to the sum of the existing variables.

% create a same table
LF_1 = 1;
LF_2 = -1;
LF_3 = 1;
T = table(LF_1,LF_2,LF_3)

T = 1×3 table
    LF_1    LF_2    LF_3
    ____    ____    ____

     1       -1      1  

% Create a new variable LF in the table as sum of LF_1-3
T.LF = abs(T.LF_1) + abs(T.LF_2) + abs(T.LF_3)

T = 1×4 table
    LF_1    LF_2    LF_3    LF
    ____    ____    ____    __

     1       -1      1      3 

[DavidL88]

Thank you. I did this but was looking for a way to automate it.

[Cris LaPierre]

What about this can't be automated?

[DavidL88]

Thanks. Is there a way to recognise groups of variables/columns based on the letters prior to a "_"? So recognise group LF from LF_1, LF_2, LF_3. Rather than writing a line of code for each group - LF, RF, LPF, etc is there a code that would recognise these groupings?