How to extract the events which have more than 3 consecutive rows

Hi,

I have array of data as follows;

idx3=0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 2 1 0 0 1 0 1 1 1 1 2 2 1 1 1 0 0 1 2 2 2 1 0 0 1 1 2 2 2 1 2 2 0 1 1 2 2 2 0 2

I want to find number of events which "2" comes for more or equal 3 consecutive rows. In my data set there are 3 events which show "2" in more than 3 (row # 83-85, 91-93 and 10-102).

How can i find it in matlab?

Thanks

Answer 1

[Walter Roberson]

r=3; how many repeats
mask = idx3.' == 2;  %row
starts = strfind([false mask], [0 ones(1,r)];
stops = strfind([mask, false], [ones(1,r) 0]) + r-1;

[Sewwandhi Chadrasekara]

Thank You and it works properly.

Answer 2

[KSSV]

idx3 = [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 2 1 0 0 1 0 1 1 1 1 2 2 1 1 1 0 0 1 2 2 2 1 0 0 1 1 2 2 2 1 2 2 0 1 1 2 2 2 0 2 ];
idx = idx3==2 ;  % get logical indices of 2 
% get the positions of 2 
pos = zeros(size(idx)) ;  
pos(idx)= find(idx) ; 
% Split the positions having twos into cells 
 wrap       = [0, pos, 0] ;
 temp       = diff( wrap ~= 0 ) ;
 blockStart = find( temp == 1 ) + 1 ;
 blockEnd   = find( temp == -1 ) ;
 blocks     = arrayfun( @(bId) wrap(blockStart(bId):blockEnd(bId)), ...
                        1:numel(blockStart), 'UniformOutput', false ) ;
% Get positions which have two's                         
L = cellfun(@length,blocks) ;  % get lengths of each cell 
iwant = blocks(L==3)            % pick cells of length 3     

Reference: https://in.mathworks.com/matlabcentral/answers/104614-grouping-continuous-nonzero-in-a-row-vector

[Sewwandhi Chadrasekara]

Thank You KSSV for quick response