How to find indices of elements but keep the order unchanged?

Hi all,

I have a cell array ch_names of channel names and I would like to get indexes of certain channels that I have given in pickCh. I have done this as follows:

Idx = find(ismember(ch_names,pickCh));

However, this gives the indexes in increasing order. Is there any better way than using a loop to keep the order of the indexes as it is in pickCh?

Thank you already in advance!

Regards, Maria

Answer 1

[Roger Stafford]

   [tf,loc] = ismember(ch_names,pickCh);
   [~,p] = sort(loc(tf));
   idx = find(tf);
   idx = idx(p);

(This assumes this are no repetitions in 'pickCh'. Otherwise there is ambiguity as to the proper ordering.)

[ibrahim Salim]

Hello, I used this code but I'v changed the first line with : [tf,loc] = cellfun(@(subc) ismember(pickCh, subc,'rows'), ch_names); to seek about a specific row. This line was slow. could you please help me to speed up run time by using the same command or another one.

Thanks

Answer 2

[Maria]

Thanks a lot! This seems to work.

-Maria