# Replacing Negative Values in Table with Previous Value in Column

7 views (last 30 days)
Stef1998 on 22 Nov 2021
Answered: Peter Perkins on 23 Nov 2021
I have a table 17520x5, in the last 2 columns I would like to replace all negative values with the previous value in that column. This is what I have tried so far and it is not working I still get negative values shown.
My table (T) had 5 columns, variable labels are (A, B, C, D, E) for each column for example
D(D < 0) = NaN;
E(E < 0) = NaN;
T(:, {'D', 'E'}) = fillmissing(T(:,{'D', 'E'}), 'previous');
disp(T)

Matt J on 22 Nov 2021
Edited: Matt J on 22 Nov 2021
T(:, {'D', 'E'}) = num2cell( fillmissing([D,E], 'previous') );
Stef1998 on 22 Nov 2021
Thank you so much! It worked

### More Answers (1)

Peter Perkins on 23 Nov 2021
Stef, as near as I can tell, the only thing wrong with your original solution is that D and E are in T, not in the workspace. The following works fine, including repeated negative values and negative values in the first row. There's no need to explicitly pull D and E out of the table. Using Matt's setup:
>> T = array2table(rand(4,5)-0.5 ,'Var',["A" "B" "C" "D" "E"])
T =
4×5 table
A B C D E
________ ________ _________ ________ _________
-0.33782 -0.33435 0.18921 -0.27102 0.038342
0.29428 0.10198 0.24815 0.41334 0.49613
-0.18878 -0.23703 -0.049458 -0.34762 -0.42182
0.028533 0.15408 -0.41618 0.32582 -0.057322
>> T.D(T.D < 0) = NaN;
>> T.E(T.E < 0) = NaN
T =
4×5 table
A B C D E
________ ________ _________ _______ ________
-0.33782 -0.33435 0.18921 NaN 0.038342
0.29428 0.10198 0.24815 0.41334 0.49613
-0.18878 -0.23703 -0.049458 NaN NaN
0.028533 0.15408 -0.41618 0.32582 NaN
>> T(:, ["D" "E"]) = fillmissing(T(:,["D" "E"]), 'previous')
T =
4×5 table
A B C D E
________ ________ _________ _______ ________
-0.33782 -0.33435 0.18921 NaN 0.038342
0.29428 0.10198 0.24815 0.41334 0.49613
-0.18878 -0.23703 -0.049458 0.41334 0.49613
0.028533 0.15408 -0.41618 0.32582 0.49613

R2021b

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