Octave has a limited number of functions for managing sets of data, where a set is defined as a collection of unique elements. In Octave a set is represented as a vector of numbers.
Return the unique elements of x, sorted in ascending order. If the input x is a vector then the output is also a vector with the same orientation (row or column) as the input. For a matrix input the output is always a column vector. x may also be a cell array of strings.
If the optional argument
"rows"is supplied, return the unique rows of x, sorted in ascending order.If requested, return index vectors i and j such that
x(i)==yandy(j)==x.Additionally, if i is a requested output then one of
"first"or"last"may be given as an input. If"last"is specified, return the highest possible indices in i, otherwise, if"first"is specified, return the lowest. The default is"last".