Look for Values in next column (max. 5 Values next)

I have a variable 1080x2. If there is a number (unequal 0) in column 1 (A), it should look in the 2nd column (B) up to 5 rows/values (not equal 0) further and take the last value (which is not equal 0) and add it to a new column (C). If there is no value found within 5 rows, then insert the value from 1st column (A).

The example datas are attached. I think ts more understandable as a excel example: Yellow are the values from 1st column and green are the founded values.

0 0

0 0

0 0

2 2

0 0

0 3

0 -5

0 0

0 0

0 0

-4 0

0 1

0 9

0 0

0 0

0 0

-1 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

Answer 1

[DGM]

This could be done without a loop, but it gets clumsy and awkward. I'll just use a loop.

A = [0 0;
    0 0;
    0 0;
    2 2;
    0 0;
    0 3;
    0 -5;
    0 0;
    0 0;
    0 0;
    -4 0;
    0 1;
    0 9;
    0 0;
    0 0;
    0 0;
    -1 0;
    0 0;
    0 0;
    0 0;
    0 0;
    0 0;
    0 0;
    0 0];

nahead = 5; % number of elements to look ahead

% add new column
A = [A,zeros(size(A,1),1)];
% find nonzero elements of col1
c1occurrence = find(A(:,1)~=0);

for occ = 1:numel(c1occurrence)
    % make sure to limit the index so it doesn't run off the end
    regionahead = A(min(c1occurrence(occ)+(0:nahead-1),size(A,1)),2);
    lastvalloc = find(regionahead~=0,1,'last'); % location of last nz value
    if isempty(lastvalloc)
        A(c1occurrence(occ),3) = A(c1occurrence(occ),1);
    else
        A(c1occurrence(occ)+lastvalloc-1,3) = A(c1occurrence(occ)+lastvalloc-1,2);
    end
end
A

gives

A =
     0     0     0
     0     0     0
     0     0     0
     2     2     0
     0     0     0
     0     3     0
     0    -5    -5
     0     0     0
     0     0     0
     0     0     0
    -4     0     0
     0     1     0
     0     9     9
     0     0     0
     0     0     0
     0     0     0
    -1     0    -1
     0     0     0
     0     0     0
     0     0     0
     0     0     0
     0     0     0
     0     0     0
     0     0     0

[Tommy Schumacher]

great work.THX

Answer 2

[Jan]

FileData = load('example.mat');
Data     = FileData.numbers;
index    = find(Data(:, 1));
for k = 1:numel(index)
    c    = index(k);
    b    = Data(c:c+4, 2);  % Safer: Data(c:min(c+4, height(Data)), 2)
    last = find(b, 1, 'last');
    if isempty(last)
        Data(c, 3) = Data(c, 1);
    else
        Data(c + last - 1, 3) = b(last);
    end
end

[Tommy Schumacher]

THX works too! :)