26. Sets

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.

Function File: unique (x)

Function File: unique (x, "rows")

Function File: unique (…, "first")

Function File: unique (…, "last")

Function File: [y, i, j] = unique (…)

Return the unique elements of x, sorted in ascending order. If x is a row vector, return a row vector, but if x is a column vector or a matrix return a column vector.

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)==y and y(j)==x.

Additionally, one of "first" or "last" may be given as an argument. If "last" is specified, return the highest possible indices in i, otherwise, if "first" is specified, return the lowest. The default is "last".

See also: union, intersect, setdiff, setxor, ismember.