[37] | 1 | function [c,ia] = setdiff(a,b,flag) |
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| 2 | %SETDIFF Set difference. |
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| 3 | % SETDIFF(A,B) when A and B are vectors returns the values |
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| 4 | % in A that are not in B. The result will be sorted. A and B |
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| 5 | % can be cell arrays of strings. |
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| 6 | % |
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| 7 | % SETDIFF(A,B,'rows') when A are B are matrices with the same |
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| 8 | % number of columns returns the rows from A that are not in B. |
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| 9 | % |
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| 10 | % [C,I] = SETDIFF(...) also returns an index vector I such that |
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| 11 | % C = A(I) (or C = A(I,:)). |
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| 12 | % |
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| 13 | % See also UNIQUE, UNION, INTERSECT, SETXOR, ISMEMBER. |
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| 14 | |
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| 15 | % Copyright 1984-2003 The MathWorks, Inc. |
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| 16 | % $Revision: 1.5 $ $Date: 2005/02/09 22:08:06 $ |
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| 17 | |
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| 18 | % Cell array implementation in @cell/setdiff.m |
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| 19 | |
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| 20 | nIn = 2; |
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| 21 | isrows = 0; |
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| 22 | |
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| 23 | rowsA = size(a,1); |
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| 24 | colsA = size(a,2); |
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| 25 | rowsB = size(b,1); |
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| 26 | colsB = size(b,2); |
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| 27 | |
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| 28 | rowvec = ~((rowsA > 1 & colsB <= 1) | (rowsB > 1 & colsA <= 1) | isrows); |
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| 29 | |
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| 30 | nOut = 1; |
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| 31 | |
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| 32 | |
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| 33 | numelA = length(a); |
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| 34 | numelB = length(b); |
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| 35 | |
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| 36 | if prod(size(a))~=numelA | prod(size(b))~=numelB |
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| 37 | error('MATLAB:SETDIFF:AandBvectorsOrRowsFlag', ... |
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| 38 | 'A and B must be vectors or ''rows'' must be specified.'); |
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| 39 | end |
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| 40 | |
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| 41 | % Handle empty arrays. |
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| 42 | |
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| 43 | if (numelA == 0) |
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| 44 | % Predefine outputs to be of the correct type. |
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| 45 | c = a([]); |
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| 46 | ia = []; |
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| 47 | % Ambiguous if no way to determine whether to return a row or column. |
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| 48 | ambiguous = (rowsA==0 & colsA==0) & ... |
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| 49 | ((rowsB==0 & colsB==0) | numelB == 1); |
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| 50 | if ~ambiguous |
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| 51 | c = reshape(c,0,1); |
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| 52 | ia = reshape(ia,0,1); |
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| 53 | end |
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| 54 | elseif (numelB == 0) |
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| 55 | % If B is empty, invoke UNIQUE to remove duplicates from A. |
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| 56 | if nOut <= 1 |
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| 57 | c = unique(a); |
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| 58 | else |
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| 59 | [c,ia] = unique(a); |
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| 60 | end |
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| 61 | return |
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| 62 | |
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| 63 | % Handle scalar: one element. Scalar A done only. |
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| 64 | % Scalar B handled within ISMEMBER and general implementation. |
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| 65 | |
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| 66 | elseif (numelA == 1) |
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| 67 | if ~ismember(a,b) |
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| 68 | c = a; |
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| 69 | ia = 1; |
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| 70 | else |
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| 71 | c = []; |
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| 72 | ia = []; |
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| 73 | end |
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| 74 | return |
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| 75 | |
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| 76 | % General handling. |
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| 77 | |
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| 78 | else |
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| 79 | |
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| 80 | % Convert to columns. |
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| 81 | a = a(:); |
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| 82 | b = b(:); |
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| 83 | |
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| 84 | % Convert to double arrays, which sort faster than other types. |
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| 85 | |
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| 86 | whichclass = class(a); |
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| 87 | isdouble = strcmp(whichclass,'double'); |
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| 88 | |
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| 89 | if ~isdouble |
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| 90 | a = double(a); |
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| 91 | end |
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| 92 | |
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| 93 | if ~strcmp(class(b),'double') |
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| 94 | b = double(b); |
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| 95 | end |
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| 96 | |
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| 97 | % Call ISMEMBER to determine list of non-matching elements of A. |
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| 98 | tf = ~(ismember(a,b)); |
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| 99 | c = a(tf); |
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| 100 | |
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| 101 | % Call UNIQUE to remove duplicates from list of non-matches. |
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| 102 | if nargout <= 1 |
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| 103 | c = unique(c); |
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| 104 | else |
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| 105 | [c,ndx] = unique(c); |
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| 106 | |
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| 107 | % Find indices by using TF and NDX. |
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| 108 | where = find(tf); |
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| 109 | ia = where(ndx); |
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| 110 | end |
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| 111 | |
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| 112 | % Re-convert to correct output data type using FEVAL. |
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| 113 | if ~isdouble |
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| 114 | c = feval(whichclass,c); |
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| 115 | end |
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| 116 | end |
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| 117 | |
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| 118 | % If row vector, return as row vector. |
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| 119 | if rowvec |
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| 120 | c = c.'; |
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| 121 | if nOut > 1 |
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| 122 | ia = ia.'; |
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| 123 | end |
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| 124 | end |
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| 125 | |
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| 126 | |
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| 127 | % Automatically deblank strings |
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| 128 | if ischar(a) |
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| 129 | c = deblank(c); |
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| 130 | end |
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