Find the begining and ending on nan sequence and store

Hi,

A = [7 9;NaN 9; NaN NaN; 4 NaN; 6 7;7 9;NaN 9; NaN NaN; 4 NaN; 6 7]

In both columns, i got 2 sequences of NaN's of length 2.

For each column i want to store the begining index and ending index of each sequence, and the length of it.

To something like:

result = cell(#number of NaN sequences of A), Size(A,2))
result = (2,3,2) (3,4,2)
         (7,8,2) (8,9,2)

And "result" could be a cell, where the column of "result" is all calculations related to column 1 of A.

hope it was clear enough,

Thanks

TLDR: I can only find the index of NaN values in my matrix A, i need a way to find the begining and end of each sequence and their length per column.

Answer 1

[Stephen23]

>> A = [7,9;NaN,9;NaN,NaN;4,NaN;6,7;7,9;NaN,9;NaN,NaN;4,NaN;6,7]
A =
     7     9
   NaN     9
   NaN   NaN
     4   NaN
     6     7
     7     9
   NaN     9
   NaN   NaN
     4   NaN
     6     7
>> T = false(1,size(A,2));
>> D = diff([T;isnan(A);T],1,1);
>> [Rb,Cb] = find(D>0);
>> [Re,Ce] = find(D<0);
>> [Rb,Re-1,Re-Rb,Cb] % [start,end,length,column]
ans =
 2   3   2   1
 7   8   2   1
 3   4   2   2
 8   9   2   2

[Tiago Dias]

Thanks, works like a charm :)