dismember or intersect

I have 2 cell arrays that have both double and characters in it. For plotting purposes, I'd like to create a 3rd array that is the size of the first array but only has the values of the second. Example:

a = {1 3 'tom';2 4 'dave'; 4 6 'mary'; 7 8 'daryl'}
b = {1 3 'tom'; 4 6 'marry'}

c = nan(size(a));

what can I do to get c to look like:

1 3 'tom'
nan nan nan
4 6 'mary'
nan nan nan

I know with an array of all numbers I could do something like: a = cell2mat(a); b = cell2mat(b); c = nan(size(a)); is = dismember(a, b); z(is) = a(is);

how can I do the same thing with strings in the array?

Thanks for your help

[Geoff]

By the way, typo on your definition of b. I assume (by your value for c) that you meant 'mary', not 'marry'.

Answer 1

[Geoff]

You can still use ismember on the 3rd column:

memb3 = ismember(a(:,3),b(:,3));

And a dirty little number on the other two:

memb12 = all(ismember(cell2mat(a(:,1:2)), cell2mat(b(:,1:2))),2);

Then:

is = memb12 & memb3;

[Trader]

Geoff - thanks that worked pretty well. I couldn't get is = memb12 & memb3; to work because of the demension of my array. is = cat(2, member12, memb3) works.

[Geoff]

Did you use my code exactly as written? The '2' in the call to 'all' is important. You should end up with memb12 and memb3 being both row-vectors. Then to get 'c' you do:

c = a(is,:);

[Geoff]

(or did I mean column-vectors?!) =)