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1 ## Copyright (C) 2000-2001 Paul Kienzle |
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2 ## |
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3 ## This program is free software; you can redistribute it and/or modify |
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4 ## it under the terms of the GNU General Public License as published by |
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5 ## the Free Software Foundation; either version 2 of the License, or |
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6 ## (at your option) any later version. |
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7 ## |
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8 ## This program is distributed in the hope that it will be useful, |
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9 ## but WITHOUT ANY WARRANTY; without even the implied warranty of |
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10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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11 ## GNU General Public License for more details. |
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12 ## |
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13 ## You should have received a copy of the GNU General Public License |
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14 ## along with this program; if not, write to the Free Software |
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15 ## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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16 |
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17 ## -*- texinfo -*- |
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18 ## @deftypefn {Function File} {} unique (@var{x}) |
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19 ## |
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20 ## Return the unique elements of @var{x}, sorted in ascending order. |
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21 ## If @var{x} is a row vector, return a row vector, but if @var{x} |
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22 ## is a column vector or a matrix return a column vector. |
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23 ## |
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24 ## @deftypefnx {Function File} {} unique (@var{A}, 'rows') |
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25 ## |
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26 ## Return the unique rows of @var{A}, sorted in ascending order. |
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27 ## |
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28 ## @deftypefnx {Function File} {[@var{y}, @var{i}, @var{j}] = } unique (@var{x}) |
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29 ## |
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30 ## Return index vectors @var{i} and @var{j} such that @code{x(i)==y} and |
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31 ## @code{y(i)==x}. |
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32 ## |
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33 ## @end deftypefn |
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34 ## @seealso{union, intersect, setdiff, setxor, ismember} |
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35 |
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36 function [y, i, j] = unique (x, r) |
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37 |
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38 if (nargin < 1 || nargin > 2 || (nargin == 2 && ! strcmp (r, "rows"))) |
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39 usage ("unique (x) or unique (x, 'rows')"); |
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40 endif |
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41 |
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42 if (nargin == 1) |
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43 n = prod (size (x)); |
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44 else |
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45 n = size (x, 1); |
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46 endif |
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47 |
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48 y = x; |
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49 if (n < 1) |
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50 i = j = []; |
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51 return; |
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52 elseif (n < 2) |
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53 i = j = 1; |
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54 return; |
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55 endif |
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56 |
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57 if (isstr (x)) |
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58 y = toascii (y); |
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59 endif |
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60 |
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61 if (nargin == 2) |
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62 [y, i] = sortrows (y); |
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63 match = all ((y(1:n-1,:) == y(2:n,:))'); |
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64 idx = find (match); |
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65 y(idx,:) = []; |
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66 else |
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67 if (size (y, 1) != 1) |
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68 y = y(:); |
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69 endif |
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70 [y, i] = sort (y); |
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71 match = y(1:n-1) == y(2:n); |
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72 idx = find (match); |
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73 y(idx) = []; |
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74 endif |
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75 |
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76 ## I don't know why anyone would need reverse indices, but it |
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77 ## was an interesting challenge. I welcome cleaner solutions. |
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78 if (nargout >= 3) |
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79 j = i; |
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80 j(i) = cumsum (prepad (! match, n, 1)); |
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81 endif |
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82 i(idx) = []; |
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83 |
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84 if (isstr (x)) |
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85 y = setstr (y); |
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86 endif |
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87 |
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88 endfunction |
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89 |
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90 %!assert(unique([1 1 2; 1 2 1; 1 1 2]),[1;2]) |
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91 %!assert(unique([1 1 2; 1 0 1; 1 1 2],'rows'),[1 0 1; 1 1 2]) |
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92 %!assert(unique([]),[]) |
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93 %!assert(unique([1]),[1]) |
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94 %!assert(unique([1 2]),[1 2]) |
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95 %!assert(unique([1;2]),[1;2]) |
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96 %!assert(unique([1,NaN,Inf,NaN,Inf]),[1,Inf,NaN,NaN]) |
