How to find column where 0 turns to 1 for each row

3 views (last 30 days)
Hello!
I would like to be able to find the column (or column title) for each row where the 0 turns to 1.
I have attached example rows (egcolumnsep.mat), so for example for row 5, I would like it to return column 20 (or Bins_11). I would like an output for all the rows though. Some rows might have only 0's (this can be NaN). This basically gives me the reaction time for each row.
Thank you for your help! =)

Accepted Answer

Bruno Luong
Bruno Luong on 15 Jul 2022
Edited: Bruno Luong on 15 Jul 2022
load('egcolumnsep.mat');
c1 = find(strcmp(DATAb1.Properties.VariableNames,'Bins_1')); % == 10
% Extract relevant data
A = table2array(DATAb1(:,c1:end));
if ~all(ismember(A,[0 1]),'all')
error('Data must be 0 or 1')
end
[cols,rows] = find(diff(A.')==1);
cols = cols+c1;
Idx01 = table(rows,cols)
Idx01 = 37×2 table
rows cols ____ ____ 1 468 1 499 1 855 1 890 2 196 3 452 3 487 3 531 3 828 3 860 4 306 4 338 4 370 4 404 4 434 4 468
  2 Comments
Tanika Bawa
Tanika Bawa on 15 Jul 2022
Thank you! Do you know how I could get it so that I only get ther first transition from 0 to 1?
Bruno Luong
Bruno Luong on 15 Jul 2022
Edited: Bruno Luong on 15 Jul 2022
Why didn't tell us that you are interested only the first transition in the question?
You can call this statement after the above scriot
groupsummary(Idx01, 'rows','min')
or start from scratch
load('egcolumnsep.mat');
c1 = find(strcmp(DATAb1.Properties.VariableNames,'Bins_1')); % == 10
% Extract relevant data
A = table2array(DATAb1(:,c1:end));
if ~all(ismember(A,[0 1]),'all')
error('Data must be 0 or 1')
end
[a,cols] = max(A,[],2);
cols = (cols+c1-1) .* (a==1) % returns 0 if no transition 0->1 is found
cols = 5×1
468 196 452 306 20

Sign in to comment.

More Answers (1)

Jonas
Jonas on 14 Jul 2022
Edited: Jonas on 14 Jul 2022
yourMat=[0 0 0 0 0;
0 1 1 0 0;
0 0 0 1 0];
where=arrayfun(@(idx)find(diff(yourMat(idx,:))==1,1,'first')+1,1:size(yourMat,1),'UniformOutput',false)'
where = 3×1 cell array
{1×0 double} {[ 2]} {[ 4]}
an empty cell shows that there was not such a change
you could set it to NaN and convert to an normal array by
where{cellfun('isempty',where)}=NaN
where = 3×1 cell array
{[NaN]} {[ 2]} {[ 4]}
where=cell2mat(where)
where = 3×1
NaN 2 4
  3 Comments
Jonas
Jonas on 14 Jul 2022
you can convert your table to a matrix before, e.g. yourTable{:,:} or table2array()
Tanika Bawa
Tanika Bawa on 14 Jul 2022
I did try that and it doesn't really let me do it unfortunately. It gives me this error:
"Unable to concatenate the specified table variables.
Caused by:
Error using categorical/cat (line 56)
Unable to concatenate a double array and a categorical array."
I do need to keep all the columns (because in the end I just want to add a column at the end with the results from this)

Sign in to comment.

Categories

Find more on Matrices and Arrays in Help Center and File Exchange

Products


Release

R2020b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!