multisetdiff

like setdiff, but any repeated elements of A are removed only once for each time they occur in B

Description

setdiff for multisets. multisetdiff(A,B) removes repeated elements of A only once for each time they occur in B.

Example:
multisetdiff([1,1,2,2],[1,1,2]) % returns 2

To work with cell arrays of strings or using the rows feature this version requires LEXCMP (see below). The current version does not work for non-string cell arrays (unless you have an implementation of SORT for cell arrays). Non-cell arrays can in principle be any objects for which SORT, SIGN, MINUS and comparison operations are defined.

See the help for more details.

Acknowledgements

The author wishes to acknowledge the following in the creation of this submission:
lexcmp

• MATLAB release: MATLAB 7.8 (R2009a)
• Other Files: license.txt, ; multisetdiff.m

[Jos (10584)]

Nice utility! Just a thought, for numerical vectors, this might be more convenient:

C = union(A,B) ;
res = C(histc(A,C) > histc(B,C))

To deal with rows of matrices or cell array strings, one could convert A and B into indices using, e.g., the third output of unique.

[Jos (10584)]

Please ignore my previous thought as it is incorrect !!