Array indices must be positive integers or logical values.

rng(0)
shuffledIndices = randperm(height(gTruth));
idx = floor(0.8 * height(gTruth));

trainingIdx = 1:idx;
trainingDataTbl = gTruth(shuffledIndices(trainingIdx),:);

testIdx = trainingIdx(end)+1 : length(shuffledIndices);
testDataTbl = gTruth(shuffledIndices(testIdx),:);

Answer 1

[Walter Roberson]

rng(0)

That line would have a problem if you had a variable named rng instead of function rng being called.

shuffledIndices = randperm(height(gTruth));

That line could have a problem if you have a variable named height instead of function height being called, in the circumstancd that gTruth had any values that did not happen to be positive integers.

idx = floor(0.8 * height(gTruth));

That line could have a problem if you have a variable named floor instead of function floor being called.

If height(gTruth) is 0 or 1 then the floor() would return 0, giving idx = 0 . In that case trainingIdx = 1:idx; would assign empty to trainingIdx . And if trainingIdx is empty then your later trainingIdx(end)+1 would be trainingIdx(0)+1 which would give indexing problems.