MATLAB: How to make a legend for data organized into colours in a bar plot

bar graphlegendMATLAB

Hello, I have data (see attached figure) which is grouped together by colour. I would like to have a legend that which explains what each colour grouping is defined by. I can only find legend creation questions about creating legends on the actual x-axis data, instead of the colour by which I organized it.
Is there a way to do this? I organized my data by colour as follows:
for i = 1:length(Names)
    switch Names(i)
        case{'Pu','Am','Np','Cm'}
            Yield.CData(i,:) = [255 0 0];
        case{'Mo','Ru','Tc','Rh','Zn','Ga'}
             Yield.CData(i,:) = [0 255 0];
        case{'Ce','Nd','Eu','Sm','Sc','Y','La'}
             Yield.CData(i,:) = [255 255 0]; 
        case{'Li','Na','K','Rb','Cs','Fr'}
            Yield.CData(i,:) = [0 0 0];
        case{'O','Xe','Te'}
             Yield.CData(i,:) = [255 255 255];
    end
end
If someone could provide an answer or some insight I would greatly appreicate it.
~ Dan

Best Answer

OK, with your data file...
[Yield,Elements] = xlsread('test.xlsx'); 
[YS,iY]=sort(Yield,'descend');              % index to plot by size
FigureName = '';XaxisLabel ='Element';YaxisLabel='Yield (atomic %)';
hF=figure('Name',FigureName,'color','white');
hBY = bar(YS);         % use different, identifiable variable for handle
hBY.FaceColor = 'flat';
for i = 1:length(Elements)
  switch Elements{iY(i)}                       % get in sorted order
    case{'Pu','Am','Np','Cm'}
      hBY.CData(i,:) = [255 0 0];           % red for actinides
    case{'Mo','Ru','Tc','Rh','Zn','Ga'}
      hBY.CData(i,:) = [0 255 0];           % green for noble metals
    case{'Ce','Nd','Eu','Sm','Sc','Y',}
      hBY.CData(i,:) = [0 0 255];           % blue for lanthanides (R.E.E.)
    case{'Li','Na','K','Rb','Cs','Fr'}
      hBY.CData(i,:) = [0 0 0];             % black for alkali-metal halides
    case{'O','Xe','He','Ne','Ar','Kr',}
      hBY.CData(i,:) = [255 255 255];       % white for non-metals

  end
end
hAx=gca;                                    % axes handle for munging with
hAx.XTick=1:numel(Y);
hAx.XTickLabel=Elements(iY);
hAY.YAxis.TickLabelFormat='%0.3f';          % set consistent format string
xlabel('Element','FontName','Optima','FontSize',10);
ylabel('Yield (atomic %)','FontName','Optima','FontSize',10);
title('Yield by Element Classification','FontName','Optima','FontSize',16);
% Now add dummy bar plot to make legends match colors
hold on
% colors -- desired color for each type/class
%co=get(groot,'defaultAxesColorOrder');              % get current axes color order
colors=[[1 0 0]; ...                                % red for actinides
        [0 1 0]; ...                                % green for noble metals
        [0 0 1]; ...                                % blue for lanthanides (R.E.E.)
        [0 0 0]; ...                                % black for alkali-metal halides
        [1 1 1]];                                   % white for non-metals
nColors=size(colors,1);                             % make variable so can change easily
labels={'Actinide';'Noble metal';'Lanthanide';'Alkali halide';'Non-metal'};
hBLG = bar(nan(2,nColors));         % the bar object array for legend
for i=1:nColors
  hBLG(i).FaceColor=colors(i,:);
end
hLG=legend(hBLG,labels,'location','northeast');
producesuntitled.jpg
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