How to separate a column into rows based on the element of a different column?
1 view (last 30 days)
Show older comments
Md Shahidullah Kawsar
on 30 Oct 2018
Commented: Md Shahidullah Kawsar
on 30 Oct 2018
Input: a = {1 2; 2 3; 3 5; -1 6; 5 7; 6 8; 7 9; 8 10; -1 11};
I have a 9x2 cell array matrix. I need my output this way: if the element in column 1 == -1, it will create a new row from the 1st element of column 2 to the element of column 2 until -1 in column 1 (inclusive). Then if -1 appears again in the first column, it will create a new row starting after the previous endpoint of column 2 to the element in column 2 until -1 appears in column 1 (inclusive).
Expected output: b = {2 3 5 6; 7 8 9 10 11}
I was trying b = a(cat(1,a{:,1}) >= -1 ,2:2).' but couldn't make separate rows. How can I do it?
2 Comments
Accepted Answer
Stephen23
on 30 Oct 2018
Edited: Stephen23
on 30 Oct 2018
This is a lot easier if you simply store the scalar numeric values in one numeric array (use cell2mat if required):
>> A = [1,2;2,3;3,5;-1,6;5,7;6,8;7,9;8,10;-1,11]
A =
1 2
2 3
3 5
-1 6
5 7
6 8
7 9
8 10
-1 11
Method one: diff and mat2cell:
>> X = diff([0;find(A(:,1)==-1)]);
>> C = mat2cell(A(:,2),X,1);
>> C{:}
ans =
2
3
5
6
ans =
7
8
9
10
11
Method two: cumsum and accumarray:
>> X = cumsum([true;A(1:end-1,1)==-1]);
>> C = accumarray(X,A(:,2),[],@(v){v});
>> C{:}
ans =
2
3
5
6
ans =
7
8
9
10
11
More Answers (0)
See Also
Categories
Find more on Cell Arrays in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!