## Copyright (C) 2000-2015 Paul Kienzle ## Copyright (C) 2008-2009 Jaroslav Hajek ## ## This file is part of Octave. ## ## Octave is free software; you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 3 of the License, or (at ## your option) any later version. ## ## Octave is distributed in the hope that it will be useful, but ## WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ## General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, see ## . ## -*- texinfo -*- ## @deftypefn {} {} unique (@var{x}) ## @deftypefnx {} {} unique (@var{x}, "rows") ## @deftypefnx {} {[@var{y}, @var{i}, @var{j}] =} unique (@dots{}) ## @deftypefnx {} {[@var{y}, @var{i}, @var{j}] =} unique (@dots{}, "first") ## @deftypefnx {} {[@var{y}, @var{i}, @var{j}] =} unique (@dots{}, "last") ## @deftypefnx {} {[@var{y}, @var{i}, @var{j}] =} unique (@dots{}, "stable") ## @deftypefnx {} {[@var{y}, @var{i}, @var{j}] =} unique (@dots{}, "sorted") ## @deftypefnx {} {[@var{y}, @var{i}, @var{j}] =} unique (@dots{}, "stable") ## @deftypefnx {} {[@var{y}, @var{i}, @var{j}] =} unique (@dots{}, "legacy") ## Return the unique elements of @var{x}, sorted in ascending order by default. ## ## If the input @var{x} is a column vector then return a column vector; ## Otherwise, return a row vector. @var{x} may also be a cell array of strings. ## ## If the optional argument @qcode{"rows"} is given then return the unique ## rows of @var{x}, sorted in ascending order by default. The input must be a ## 2-D matrix to use this option. ## ## If requested, return index vectors @var{i} and @var{j} such that ## @code{@var{y} = @var{x}(@var{i})} and @code{@var{x} = @var{y}(@var{j})}. ## These are row vectors if @qcode{"legacy"} is specified, or columns otherwise. ## ## The option @qcode{"stable"} returns a vector whose elements appear in the ## same order as they were in @var{x}, whereas @qcode{"sorted"} returns the ## elements in increasing order. The default is @qcode{"sorted"}. ## ## Additionally, one of @qcode{"first"} or ## @qcode{"last"} may be given as an input. If @qcode{"last"} is specified, ## return the highest possible indices in @var{i} and for @qcode{"stable"} ## ordering, otherwise, if @qcode{"first"} is specified, return the lowest. ## The default is @qcode{"last"} if @qcode{"legacy"} is set, or @qcode{"first"} ## otherwise. ## @seealso{union, intersect, setdiff, setxor, ismember} ## @end deftypefn function [y, i, j] = unique (x, varargin) if (nargin < 1) print_usage (); elseif (! (isnumeric (x) || islogical (x) || ischar (x) || iscellstr (x))) error ("unique: X must be an array or cell array of strings"); endif if (nargin > 1) ## parse options if (! iscellstr (varargin)) error ("unique: options must be strings"); endif optrows = any (strcmp ("rows", varargin)); optfirst = any (strcmp ("first", varargin)); optlast = any (strcmp ("last", varargin)); optstable = any (strcmp ("stable", varargin)); optsorted = any (strcmp ("sorted", varargin)); optlegacy = any (strcmp ("legacy", varargin)); if (optfirst && optlast) error ('unique: cannot specify both "first" and "last"'); elseif (optstable && optsorted) error ('unique: cannot specify both "stable" and "sorted"'); elseif (optfirst + optlast + optrows + optstable + optsorted + optlegacy != nargin-1) known_options = {"rows", "first", "last", "stable", "sorted", "legacy"}; for i = 2:nargin if ! any (strcmp (varargin{i}, known_options)) error ("unique: invalid option %s", varargin{i}); endif endfor endif if (optrows && iscellstr (x)) warning ('unique: "rows" is ignored for cell arrays'); optrows = false; endif if (! optlegacy && ! optlast) optfirst = true; end else optrows = false; optfirst = true; # new default in Matlab optstable = false; optlegacy = false; endif ## FIXME: The operations ## ## match = (y(1:n-1) == y(2:n)); ## y(idx) = []; ## ## are very slow on sparse matrices. Until they are fixed to be as ## fast as for full matrices, operate on the nonzero elements of the ## sparse array as long as we are not operating on rows. if (issparse (x) && ! optrows && nargout <= 1) if (nnz (x) < numel (x)) y = unique ([0; nonzeros(x)], varargin{:}); else ## Corner case where sparse matrix is actually full y = unique (full (x), varargin{:}); endif return; endif if (optrows) n = rows (x); dim = 1; else n = numel (x); dim = (rows (x) == 1) + 1; endif y = x; ## Special cases 0 and 1 if (n == 0) if (! optrows && isempty (x) && any (size (x))) if (iscellstr (y)) y = cell (0, 1); else y = zeros (0, 1, class (y)); endif endif i = j = []; return; elseif (n == 1) i = j = 1; return; endif if (optrows) if (nargout > 1 || optstable) [y, ii] = sortrows (y); else y = sortrows (y); endif match = all (y(1:n-1,:) == y(2:n,:), 2); y(match,:) = []; else if (! isvector (y)) y = y(:); endif if (nargout > 1 || optstable) [y, ii] = sort (y); else y = sort (y); endif if (iscellstr (y)) match = strcmp (y(1:n-1), y(2:n)); else match = (y(1:n-1) == y(2:n)); endif y(match) = []; endif ## Calculate output 2 first, since 3 needs perm if optstable if (isargout (2) || optstable) idx = find (match); if (optfirst) idx += 1; # in-place is faster than other forms of increment endif i = ii; if (! isargout (3)) clear ii # allow operations on i to avoid copy end i(idx) = []; if (optstable) [i perm] = sort (i); if (optrows) y = x(i,:); else y = x(i); endif endif if (! optlegacy) # New default in Matlab: return column i = i(:); endif endif if (isargout (3)) j = ii; positions = cumsum ([1; ! match(:)]); if (optstable) j(ii) = perm(positions); else j(ii) = positions; endif if (! optlegacy) j = j(:); endif endif endfunction %!assert (unique ([1 1 2; 1 2 1; 1 1 2]), [1;2]) %!assert (unique ([1 1 2; 1 0 1; 1 1 2],"rows"), [1 0 1; 1 1 2]) %!assert (unique ([]), []) %!assert (unique ([1]), [1]) %!assert (unique ([1 2]), [1 2]) %!assert (unique ([1;2]), [1;2]) %!assert (unique ([1,NaN,Inf,NaN,Inf]), [1,Inf,NaN,NaN]) %!assert (unique ({"Foo","Bar","Foo"}), {"Bar","Foo"}) %!assert (unique ({"Foo","Bar","FooBar"}'), {"Bar","Foo","FooBar"}') %!assert (unique (zeros (1,0)), zeros (0,1)) %!assert (unique (zeros (1,0), "rows"), zeros (1,0)) %!assert (unique (cell (1,0)), cell (0,1)) %!assert (unique ({}), {}) %!assert (unique ([1,2,2,3,2,4], "rows"), [1,2,2,3,2,4]) %!assert (unique ([1,2,2,3,2,4]), [1,2,3,4]) %!assert (unique ([1,2,2,3,2,4]', "rows"), [1,2,3,4]') %!assert (unique (sparse ([2,0;2,0])), [0,2]') %!assert (unique (sparse ([1,2;2,3])), [1,2,3]') %!assert (unique ([1,2,2,3,2,4]', "rows"), [1,2,3,4]') %!assert (unique (single ([1,2,2,3,2,4]), "rows"), single ([1,2,2,3,2,4])) %!assert (unique (single ([1,2,2,3,2,4])), single ([1,2,3,4])) %!assert (unique (single ([1,2,2,3,2,4]'), "rows"), single ([1,2,3,4]')) %!assert (unique (uint8 ([1,2,2,3,2,4]), "rows"), uint8 ([1,2,2,3,2,4])) %!assert (unique (uint8 ([1,2,2,3,2,4])), uint8 ([1,2,3,4])) %!assert (unique (uint8 ([1,2,2,3,2,4]'), "rows"), uint8 ([1,2,3,4]')) %!test %! [a,i,j] = unique ([1,1,2,3,3,3,4]); %! assert (a, [1,2,3,4]); %! assert (i, [2,3,6,7]); %! assert (j, [1,1,2,3,3,3,4]); %! %!test %! [a,i,j] = unique ([1,1,2,3,3,3,4]', "first"); %! assert (a, [1,2,3,4]'); %! assert (i, [1,3,4,7]'); %! assert (j, [1,1,2,3,3,3,4]'); %! %!test %! [a,i,j] = unique ({"z"; "z"; "z"}); %! assert (a, {"z"}); %! assert (i, [3]'); %! assert (j, [1;1;1]); %! %!test %! A = [1,2,3;1,2,3]; %! [a,i,j] = unique (A, "rows"); %! assert (a, [1,2,3]); %! assert (A(i,:), a); %! assert (a(j,:), A); ## Test input validation %!error unique () %!error unique ({1}) %!error unique (1, 2) %!error unique (1, "first", "last") %!error unique (1, "middle") %!error unique ({"a", "b", "c"}, "UnknownOption") %!error unique ({"a", "b", "c"}, "UnknownOption1", "UnknownOption2") %!error unique ({"a", "b", "c"}, "rows", "UnknownOption2") %!error unique ({"a", "b", "c"}, "UnknownOption1", "last") %!warning <"rows" is ignored for cell arrays> unique ({"1"}, "rows");