Index exceeds matrix problem

I have a cell array (7879x1)and I want to create a new character array that depends on this cell array. For example my first 5 character array is:

KA
KT
Zb2.Cd4t1R2
Zb2.Bd4t1R2
Zb2.Ard4t1R1
Zb2.Bd4t2R2

I write a code to form new cell array called 'Group':

for i=1:numel(cell);
  if cell{i}(3)==1;
    Group{i}='A';
    else if cell{i}(3)== 2;
      Group{i}= 'A';
      else if cell{i}(3)== 3;
        Group{i}= 'A';
        else if cell{i}(3)== 4;
          Group{i}= 'B';
          else if cell{i}(3)== 5;
            Group{i}= 'D';
            else if cell{i}(3)== 6;
              Group{i}= 'D';
            end
          end
        end
      end
    end
  end
end

but since I haven't got any value for cell{1}(3) and cell{2}(3). it gives me error. How can I solve the problem and How can I say that if cell{i} (3) has no value it should be zero. I try

else if cell{i}(3)== ''; Group{i}= '0',

but it doesn't work.

[Gokhan Kayan]

Thanks for your reply dpb I solved it with different method :)

[dpb]

So, show us! :)

Answer 1

[dpb]

In brute force, use try ... catch ... end to catch the error elements

for i=1:length(cell)
  try
    if cell{i}(3)==1;
       ...   
  catch % if err on indexing, end up here
    Group{i}= '0',
  end
end

But the code as given just begs for alternate implementations...at a bare minimum use a SWITCH construct something like

for i=1:length(cell)
  try
   c=cell{i}(3)          % pick the wanted character
    switch(c)
     case {1, 2, 3}
       Group{i}= 'A';
     case {4}
       Group{i}= 'A';
     case {5, 6}
       Group{i}= 'D';
       ...
     else
       ....
   end % switch construct
  catch % if err on indexing, end up here
    Group{i}= '0',
  end % try...catch block
end   % for...end block

but even that needs a lot of code and editing. I'm out of time, maybe somebody else will come along and illustrate the use of a "lookup table" with which you could vectorize it and make the case definitions exist in just a data table/array.

Answer 2

[Jan]

Data = {'KA', ...
        'KT', ...
        'Zb2.Cd4t1R2', ...
        'Zb2.Bd4t1R2', ...
        'Zb2.Ard4t1R1', ...
        'Zb2.Bd4t2R2'};
Pool = 'AAABDD';

Group    = cell(1, length(Data));   % Pre-allocate
Group(:) = {'0'};

for iData = 1:length(Data)
   S = Data{iData};
   if length(S) > 2
      Group{iData} = Pool(S(3) - '0');
   end
end