how to imply array of zeros and ones to my dataset, help me plz

hi guy , I've those tasks, and I did my best to get them all done, this is what I've done so far. plz help me with task3 to get it done,

 data=readData('adult.csv',',');
 hdr=fieldnames(data)
 N=length(data.income)

Task 1

Split the dataset into two subsets, say, "train" and "test", with the train set containing 80% of the data and the test set containing the remaining 20%.

Splitting means to generate a logical index of length equal to the number of observations in the dataset, with 1 for a training sample and 0 for at test sample.

Output: logical arrays called idxTrain and idxTest.

 p=0.8;     %train which is %80

 numOfOne= N*p;

 idxTrain=[ones(1, numOfOne)];                   // array of ones %80
 idxTest=[ zeros(1, N - numOfOne)];             // array of zeros %20

Task 2 using unique() convert the "race" categories into numerical indices. Then compute the popluation counts of the "race" categories.

Output: array E with the population counts of the race variable.

 x=data.race(:);
 [ux,~,idx]=unique(x);   
 idx=idx(:);  
 numbers = accumarray (idx , ones(size(idx)) );

Task 3 using accumarray compute the observed counts for the train and for the test subsets. Call tese TrainO and TestO, respectively.

Output: arrays TrainO and TestO with the race counts in each of the 2 subsets.

 TrainO=

 TestO=