Removing Rows from a Cell Array if there are less than 5 other rows with the same information in that column

I have a 2601x19 cell array called "BP2KData"

Column 3 contains animal ID numbers

Collumn 9 contains Date Strings

All data points that do not have 4 others from that animal on that day need to be removed. For example, if there are only 3 rows with information for the animal "322" on the date "9/22" all three rows must be deleted.

My code deletes everything, every-time.

I have attached my code.

I know that this is likely a tough nut to crack, I realize they way that I am currently trying to solve this problem is grossly inefficient.

Many thanks

[Star Strider]

Are you only looking at columns 3 and 9?

It might be more helpful for you to upload all — or a representative part — of your cell array, then we will have some idea of its structure, and we can ask you questions about it.

Answer 1

[Jan]

n     = size(BP2KData, 1);
keep  = false(1, n);
check = true(1, n);  % Avoid checking multiple times
for k = 1:n
  if check(k)
    matchID   = strcmp(BP2KData(:, 3), BP2KData(k, 3));
    matchDate = strcmp(BP2KData(:, 9), BP2KData(k, 9));
    match     = matchID & matchDate;
    if sum(match) >= 4
      keep(match)  = true;
      check(match) = false;
    end
  end
end

BP2KData = BP2KData(keep, :);