One way of doing one-hot encoding in Matlab

one_hot.m

% y is a vector of labels
y_one_hot = zeros( size( y, 1 ), n_classes );

% assuming class labels start from one
for i = 1:n_classes
    rows = y == i;
    y_one_hot( rows, i ) = 1;
end

y_one_hot = ind2vec(y')'; // matlab has this built-in function

Allowing all values in y (above doesn't work if any y is zero or negative):

[~, loc] = ismember(y, unique(y));
y_one_hot = ind2vec(loc')';

This is nice as it also works for cell strings:

ystr = cellstr(char('hey', 'hey', 'gurl', 'hey'));
[~, loc] = ismember(ystr, unique(ystr));
y_one_hot = ind2vec(loc')';
array2table(full(y_one_hot), 'VariableNames', unique(ystr))

y_one_hot = ind2vec(y')'; // matlab has this built-in function

y_one_hot = full(ind2vec(y',num_classes)) is a clean way to do this.