MATLAB: Remove duplicate variables depending on a variable in a second column

duplicates

Dear experts, I have a list of variables where I need to remove duplicate variables based on the variable in column 2. Variables with a '1' in column 2 are of better quality than variables with a '0'.
1) In case of duplicate variables, I want to keep the variables that have value 1 in the second column. In cases when there are multiple duplicates with a 1 then it needs to keep randomly only one variable. See example below: Here I want to keep the variable BG1028 where the data in the third column is 1.3. For BG1030, I want to keep the variable with 3.0 or 0.3 in the third column.
2) In case of duplicate variables which all have a zero in the second column then it needs to keep randomly only one variable. See example below: I need to keep one variable of BG1027 (random choice).
I hope it is clear. Im puzzling how to do this. This is the code I came up with so far with help from Kirby Fear.
ppn = [ {'BG1026';'BG1027';'BG1027';'BG1028';'BG1028';'BG1028';'BG1029';'BG1029';...
    'BG1030';'BG1030';'BG1030';'BG1030'},... % start col 2
    {'0';'0';'0';'1';'0';'0';'1';'0';'0';'1';'0';'1'},... % start col 3
    {'1.2';'2.2';'5.2';'4.2';'0.2';'8.9';'3.4';'3.0';'0.3';'1.3';'0.3';'1.7'} ];
% Storing ppn column 2 as numerical values
bPpn=cell2mat(cellfun(@(c)str2double(c),ppn(:,2),...
    'UniformOutput',false));
% Get names of duplicates
chooseNames = ppn([strcmp(ppn(1:end-1,1),ppn(2:end,1));false],1);
% Loop over chooseNames and keep one at random.
if numel(chooseNames)>0,
    for j=1:numel(chooseNames),
        dupidx=find(strcmp(chooseNames{j},ppn(:,1)));
        dupidx(randi(numel(dupidx)))=[];
        ppn(dupidx,:)=[];
    end
end

Best Answer

Give something like this a try:
 ppn = [ {'BG1026';'BG1027';'BG1027';'BG1028';'BG1028';'BG1028';'BG1029';'BG1029';...
    'BG1030';'BG1030';'BG1030';'BG1030'},... % start col 2
    {'0';'0';'0';'1';'0';'0';'1';'0';'0';'1';'0';'1'},... % start col 3
    {'1.2';'2.2';'5.2';'4.2';'0.2';'8.9';'3.4';'3.0';'0.3';'1.3';'0.3';'1.7'} ];
 [uniqNames, ia, ic] = unique(ppn(:,1));
 ia = [ia; 1+length(ic)];
 ppn_out = {}; % initialize output 
 for i = 1:length(uniqNames);
    sub = ppn(ia(i):ia(i+1)-1,:); % find only entries with uniqNames(i)
    sub = sub(find(cell2mat(sub(:,2)) == max(cell2mat(sub(:,2)))),:); % find only those entries with the maximal value in col 2
    ppn_out = [ppn_out;  sub(randi(size(sub,1)),:)]; % select one entry at random, put it in ppn_out
 end
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