Delete Entries in Cell arrays with a certain criterea

Hello I Have a cell :

   A= [2011 12 3 8 52 36]    [2019]
      [2011 12 3 8 52 40]    [2004]
      [2011 12 3 8 52 52]    [2004]
      [2011 12 3 14 50 50]   [2015]

the first row contains a Matrix with the date in yyyy mm dd HH MM SS

i need to delete the double entry for 2004 delete second or third row if the date is less distant than one day Thanks a lot

Answer 1

[Nick Counts]

This is messy, but here is an example. I'm sure there's a slick way to do this with logical indexing, but I can't quite wrap my head around it.

Sometimes a for-loop will get it done when slicker methods are elusive. I tried to comment the example, so hopefully it makes sense to you. I also added an additional row with [2004] in column 7 that is more than 1 day away, and it is correctly left alone.

   A = [[2011 12 3 8 52 36]    [2019];
        [2011 12 3 8 52 40]    [2004];
        [2011 12 5 8 52 52]    [2004];
        [2011 12 3 14 50 50]   [2015];
        [2011 12 3 8 52 52]    [2004]]

    disp('Starting with these dates:')
    datestr(datenum(deal(A(:,1:6))))

    % Find unique values in column 7
    uniqueValues = unique(A(:,7));

    % how often does each unique value from column 7 occur?
    freq = hist(A(:,7), uniqueValues);

    % find index of column 7 values that appear more than once
    nonUniqueInd = ismember(A(:,7),uniqueValues(freq>1));

    % Make a list of values that are repeated in column 7
    nonUniqueVals = A(nonUniqueInd,7)

    % we will be building an index of rows to delete
    indToRemove = [];

    % Loop through each value that is repeated. Will run on the same
    % value more than once to caputure the case when a column 7 value
    % occurs multiple times on multiple days
    for i = 1:numel(nonUniqueVals)

        % try each non-unique value from column 7
        % get the index of each occurrence of the current non-unique
        % value in the original array
        nuInd = find(A(:,7)==nonUniqueVals(i))

        % find elapsed time from first occurrence of the repeated value 
        % in column 7
        deltas = datenum(deal(A(nuInd(1),1:6)))-(datenum(deal(A(nuInd,1:6))))

        % find any time changes that are 0 or greater than 1. This
        % gives us the first occurrence and anthing on a different day
        thisIndToRemove = nuInd(find( (deltas == 0 | deltas > 1)))

        % Add indices to the running list. We could delete them here,
        % but it's a little better to build a small array of indices then
        % to keep resizing the original array, which could potential be
        % very large.
        indToRemove = vertcat(indToRemove, thisIndToRemove);

    end

    % Remove duplicates matching our conditions
    A(indToRemove,:) = [];

    disp('Here are the remaining rows');
    datestr(datenum(deal(A(:,1:6))))