Match cell arrays with different size based on two conditions in Matlab

RECCELL is a cell array with 8 columns and 30000 rows:

 C1     C2      C3          C4   C5          C6     C7    C8
'AA'    1997    19970102    1   'BACHE'     'MORI'  148   127
'AA'    1997    19970108    2   'MORGAN'     []     1595  0
'AA'    1997    19970224    3   'KEMSEC'    'FATHI' 1315  297

CONCELL is a cell array with 4 columns and 70000 rows:

 C1     C2      D3          D4
'AA'    1997    19970116    2,75
'AA'    1997    19970220    2,71
'AA'    1997    19970320    2,61

I would like to add to RECCELL the 4 columns of CONCELL only in case the C1s match and C3 and D3 (both dates) are the closest possible. For instance I would get in this example:

 C1     C2      C3         C4    C5           C6     C7    C8   C1      C2      D3          D4           

'AA'    1997    19970102    1   'BACHE'      'MORI'  148   127  'AA'    1997    19970116    2,75

'AA'    1997    19970108    2   'MORGAN'     []      1595  0    'AA'    1997    19970116    2,75

'AA'    1997    19970113    3   'KEMSEC'    'FATHI'  1315  297  'AA'    1997    19970220    2,71

To the first row of RECCELL corresponds the first row of CONCELL.
To the second row of RECCELL corresponds the first row of CONCELL.
To the third row of RECCELL corresponds the second row of CONCELL.

The code I have so far is:

[~, indCon, indREC] = intersect(CONCELL(:,1), RECCELL(:,1));
REC_CON=[RECCELL(indREC,:),CONCELL(indCon,:)];
NO_REC_CON= RECCELL(setdiff(1:size(RECCELL,1), indREC),:);

It's wrong because I cannot use intersect for a string element and because I am not considering the second condition, which is to choose the closest dates.

Can someone help me? Thank you

Solution

I would suggest to do this inside a for loop as the cells are very tall. (Note: it seems like the date format (C3/D3) in the cell is a double opposed to a string, thus needs to be converted first for using datenum)

n=size(RECCELL,1);
ind=zeros(n,1);
rd=datenum(num2str(cell2mat(CONCELL(:,3))),'yyyymmdd'); % convert double to string
for k=1:n
    a=find(ismember(CONCELL(:,1),RECCELL(k,1))==1);     % find indices of matching C1s
    if ~isempty(a)                                      % do only if there is a match for the C1s
        dnk=datenum(num2str(RECCELL{k,3}),'yyyymmdd');  % convert double to string
        [~,f]=min((rd(a)-dnk).^2);                      % find closest date of the subset a
        ind(k,1)=a(f);                                  % assign index of closest match to ind
        RECCELL(k,(end+1):(end+4))=CONCELL(ind(k,1),:); % add CONCELL to RECCELL, be aware that other rows will now display empty cells, and a row of RECCELL can keep 'growing'
    end
end

The vector ind contains the indices of the closest match in CONCELL for each entry in RECCELL. When it contains a 0, no match was found between the C1s.

Edit: One possible solution to avoid increasing the number of columns of RECCELL if multiple CONCELL entries are added to the same RECCELL entry is the following which results in a adding a single column to the RECCELL matrix:

n=size(RECCELL,1);
RECCELL{1,end+1}=[];                                    % to add a single empty column to RECCELL
ind=zeros(n,1);
rd=datenum(num2str(cell2mat(CONCELL(:,3))),'yyyymmdd'); % convert double to string
for k=1:n
    a=find(ismember(CONCELL(:,1),RECCELL(k,1))==1);     % find indices of matching C1s
    if ~isempty(a)                                      % do only if there is a match for the C1s
        dnk=datenum(num2str(RECCELL{k,3}),'yyyymmdd');  % convert double to string
        [~,f]=min((rd(a)-dnk).^2);                      % find closest date of the subset a
        ind(k,1)=a(f);                                  % assign index of closest match to ind
        if isempty(RECCELL{k,end})                      % if nothing is in this cell, add the CONCELL entry to it
            RECCELL{k,end}=CONCELL(ind(k,1),:);
        else                                            % if something is already in, add the new CONCELL entry to the cell
            RECCELL{k,end}(end+1,1:4)=CONCELL(ind(k,1),:);
        end
    end
end