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1 ## Copyright (C) 2000 Paul Kienzle |
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2 ## |
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3 ## This file is part of Octave. |
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4 ## |
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5 ## Octave is free software; you can redistribute it and/or modify it |
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6 ## under the terms of the GNU General Public License as published by |
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7 ## the Free Software Foundation; either version 2, or (at your option) |
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8 ## any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License for more details. |
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14 ## |
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15 ## You should have received a copy of the GNU General Public License |
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16 ## along with Octave; see the file COPYING. If not, write to the Free |
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17 ## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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18 ## 02110-1301, USA. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} setdiff (@var{a}, @var{b}) |
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22 ## @deftypefnx {Function File} {} setdiff(@var{a}, @var{b}, "rows") |
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23 ## Return the elements in @var{a} that are not in @var{b}, sorted in |
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24 ## ascending order. If @var{a} and @var{b} are both column vectors |
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25 ## return a column vector, otherwise return a row vector. |
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26 ## |
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27 ## Given the optional third argument @samp{"rows"}, return the rows in |
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28 ## @var{a} that are not in @var{b}, sorted in ascending order by rows. |
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29 ## @seealso{unique, union, intersect, setxor, ismember} |
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30 ## @end deftypefn |
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31 |
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32 ## Author: Paul Kienzle |
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33 ## Adapted-by: jwe |
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34 |
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35 function c = setdiff (a, b, byrows) |
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36 |
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37 if (nargin < 2 || nargin > 3) |
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38 print_usage (); |
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39 endif |
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40 |
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41 if (nargin == 3) |
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42 if (! strcmpi (byrows, "rows")) |
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43 error ("expecting third argument to be \"rows\""); |
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44 else |
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45 byrows = true; |
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46 endif |
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47 else |
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48 byrows = false; |
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49 endif |
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50 |
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51 if (byrows) |
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52 c = unique (a, "rows"); |
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53 if (! isempty (c) && ! isempty (b)) |
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54 ## Form a and b into combined set. |
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55 b = unique (b, "rows"); |
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56 [dummy, idx] = sortrows ([c; b]); |
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57 ## Eliminate those elements of a that are the same as in b. |
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58 n = length (dummy); |
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59 c(idx(find (dummy(1:n-1) == dummy(2:n))), :) = []; |
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60 endif |
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61 else |
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62 c = unique (a); |
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63 if (! isempty (c) && ! isempty (b)) |
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64 ## Form a and b into combined set. |
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65 b = unique (b); |
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66 [dummy, idx] = sort ([c(:); b(:)]); |
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67 ## Eliminate those elements of a that are the same as in b. |
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68 n = length (dummy); |
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69 c(idx(find (dummy(1:n-1) == dummy(2:n)))) = []; |
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70 ## Reshape if necessary. |
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71 if (size (c, 1) != 1 && size (b, 1) == 1) |
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72 c = c.'; |
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73 endif |
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74 endif |
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75 endif |
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76 |
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77 endfunction |
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78 |
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79 %!assert(setdiff(["bb";"zz";"bb";"zz"],["bb";"cc";"bb"],"rows"), "zz") |
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80 %!assert(setdiff(["b";"z";"b";"z"],["b";"c";"b"],"rows"), "z") |
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81 %!assert(setdiff(["b";"z";"b";"z"],["b";"c";"b"]), "z") |
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82 %!assert(setdiff([1, 1; 2, 2; 3, 3; 4, 4], [1, 1; 2, 2; 4, 4], "rows"), [3 3]) |
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83 %!assert(setdiff([1; 2; 3; 4], [1; 2; 4], "rows"), 3) |
