I get an erro message when I try this: C = {'one', 'two', 'three'; 1, 2, 3} A = {'one', 'three'; 1, 3} X= intersect(C,A,'rows')

Input A of class cell and input B of class cell must be cell arrays of strings, unless one is a string.

[Image Analyst]

C = 
    'one'    'two'    'three'
    [  1]    [  2]    [    3]
A = 
    'one'    'three'
    [  1]    [    3]

So exactly which do you want to compare? Cell-by-cell? But they're different numbers of cells wide (3 columns vs. 2 columns). Do you want to see if any cell in A lies in any cell of C regardless of which column it finds it in? So A{1,2} = 'three' but it does not occur in the corresponding location, C{1,2}, in cell array C. 'three' occurs in column 2 of A but column 3 of C - do you consider that a match or not?

Do you want to use ismember()????

[Ed Robinson]

oh dear

thanks for your patience

I meant

C = {'one', 1;'two', 2; 'three' , 3}

A = {'one', 1; 'three' , 3}

X= intersect(C,A,'rows')

Answer 1

[Walter Roberson]

http://www.mathworks.com/help/matlab/ref/intersect.html

"The 'rows' option does not support cell arrays, unless one of the inputs is either a categorical array or a datetime array."

Because of that, you are effectively getting

intersect(C,A)

which is the same as

intersect(C(:), A(:))

and this in turn will fail. You can compare strings to strings and you can compare numbers to numbers, but you cannot have a mix of strings and numbers.

You will find that unique() and ismember() are also not able to handle mixed data types.

[ROW,COL] = ndgrid(1:size(A,1), 1:size(C,1));
match_matrix = arrayfun(@(J,K) isequal(A(J,:),C(K,:)),ROW,COL);
X = C( any(match_matrix & cumsum(match_matrix,2)==1), :);

Note: the output will not be "sorted", and I did not pay attention to whether it is in the order of entries of A or in the order of entries of C. I did, however, take care to remove duplicate matches.

[Ed Robinson]

Very grateful thank you. There's a bit to think about there which i will go through. It is also very useful to know that there appears not to be a just simple solution!