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comparison scripts/set/intersect.m @ 11922:746f13936eee release-3-0-x

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improve set functions for Matlab compatibility
author Jaroslav Hajek <highegg@gmail.com>
date Fri, 16 Jan 2009 08:10:28 +0100
parents a1dbe9d80eee
children cadc73247d65
comparison
equal deleted inserted replaced
11921:166a195399f7 11922:746f13936eee
1 ## Copyright (C) 2000, 2006, 2007 Paul Kienzle 1 ## Copyright (C) 2000, 2006, 2007 Paul Kienzle
2 ## Copyright (C) 2008 Jaroslav Hajek
2 ## 3 ##
3 ## This file is part of Octave. 4 ## This file is part of Octave.
4 ## 5 ##
5 ## Octave is free software; you can redistribute it and/or modify it 6 ## Octave is free software; you can redistribute it and/or modify it
6 ## under the terms of the GNU General Public License as published by 7 ## under the terms of the GNU General Public License as published by
28 ## @code{b(ib)==c}. 29 ## @code{b(ib)==c}.
29 ## 30 ##
30 ## @end deftypefn 31 ## @end deftypefn
31 ## @seealso{unique, union, setxor, setdiff, ismember} 32 ## @seealso{unique, union, setxor, setdiff, ismember}
32 33
33 function [c, ia, ib] = intersect (a, b) 34 function [c, ia, ib] = intersect (a, b, varargin)
34 if (nargin != 2) 35
36 if (nargin < 2 || nargin > 3)
35 print_usage (); 37 print_usage ();
36 endif 38 endif
39
40 if (nargin == 3 && ! strcmpi (varargin{1}, "rows"))
41 error ("intersect: if a third input argument is present, it must be the string 'rows'");
42 endif
43
37 44
38 if (isempty (a) || isempty (b)) 45 if (isempty (a) || isempty (b))
39 c = ia = ib = []; 46 c = ia = ib = [];
40 else 47 else
41 ## form a and b into sets 48 ## form a and b into sets
42 [a, ja] = unique (a); 49 if (nargout > 1)
43 [b, jb] = unique (b); 50 [a, ja] = unique (a, varargin{:});
44 51 [b, jb] = unique (b, varargin{:});
45 c = [a(:); b(:)];
46 [c, ic] = sort (c); ## [a(:);b(:)](ic) == c
47
48 if (iscellstr (c))
49 ii = find (strcmp (c(1:end-1), c(2:end)));
50 else
51 ii = find (c(1:end-1) == c(2:end));
52 endif 52 endif
53 53
54 c = c(ii); ## The answer 54 if (nargin > 2)
55 ia = ja(ic(ii)); ## a(ia) == c 55 c = [a; b];
56 ib = jb(ic(ii+1) - length (a)); ## b(ib) == c 56 [c, ic] = sortrows (c);
57 ii = find (all (c(1:end-1,:) == c(2:end,:), 2));
58 c = c(ii,:);
59 else
60 c = [a(:); b(:)];
61 [c, ic] = sort (c); ## [a(:);b(:)](ic) == c
62 if (iscellstr (c))
63 ii = find (strcmp (c(1:end-1), c(2:end)));
64 else
65 ii = find (c(1:end-1) == c(2:end));
66 endif
67 c = c(ii);
68 endif
57 69
58 70
59 if (size (b, 1) == 1 || size (a, 1) == 1) 71 if (nargout > 1)
72 ia = ja(ic(ii)); ## a(ia) == c
73 ib = jb(ic(ii+1) - length (a)); ## b(ib) == c
74 endif
75
76
77 if (nargin == 2 && (size (b, 1) == 1 || size (a, 1) == 1))
60 c = c.'; 78 c = c.';
61 endif 79 endif
62 endif 80 endif
63 81
64 endfunction 82 endfunction
72 %! assert( c,[1 3 5 7]); 90 %! assert( c,[1 3 5 7]);
73 %! assert(ia,[8 1 7 5]); 91 %! assert(ia,[8 1 7 5]);
74 %! assert(ib,[5 1 2 6]); 92 %! assert(ib,[5 1 2 6]);
75 %! assert(a(ia),c); 93 %! assert(a(ia),c);
76 %! assert(b(ib),c); 94 %! assert(b(ib),c);
95 %!test
96 %! a = [1,1,2;1,4,5;2,1,7];
97 %! b = [1,4,5;2,3,4;1,1,2;9,8,7];
98 %! [c,ia,ib] = intersect(a,b,'rows');
99 %! assert(c,[1,1,2;1,4,5]);
100 %! assert(ia,[1;2]);
101 %! assert(ib,[3;1]);
102 %! assert(a(ia,:),c);
103 %! assert(b(ib,:),c);