MATLAB: Error using classperf

cv

I have a code
data=[0.5 .3 0.6 0.5;0.2 0.3 0.5 0.9;0.1 0.7 0.2 0.8;0.5 .3 0.6 0.5;0.2 0.3 0.5 0.9;0.1 0.7 0.2 0.8]
TrainData=data(:,1:2)
 TestVector=data(:,3:4)
 groups=[0;1;1;0;1;1]
   cvFolds = crossvalind('kfold', groups, 10);  %# get indices of 10-fold CV %# get indices of 10-fold CV
  cp = classperf(groups);  
  for i = 1:10   
%   testIdx = (cvFolds == i);                %# get indices of test instances
%    trainIdx = ~testIdx; 
   Training=(data(:,1:2));
   TestVector=data(:,3:4)
 Group=groups;
 TreeObject=TreeBagger(50,Training,Group,'NVarToSample','all');
   [YFIT,scores] = predict(TreeObject,TestVector);
  %cp = classperf(cp, YFIT, testIdx)
  cp = classperf(cp, YFIT)
end
I get error
Error using classperf (line 230)
When the class labels of the CP object are numeric, the output
of the classifier must be all non-negative integers or NaN's.
Error in yass (line 30)
cp = classperf(cp, YFIT)

Best Answer

See my response in http://www.mathworks.com/matlabcentral/answers/34771-classifier
In your code snippet, the error is caused by TreeBagger returning predicted class labels as a cell array of strings, while the class labels (groups variable) passed to classperf are numeric. To avoid this, convert groups to a cell array of strings:
groups = cellstr(num2str(groups))
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