help extracting data from cell arrays

Hi, i have a set of data within a cell array which can vary put looks like this

col1---col2---col3---col4 smpA smpB smpC smpD smpE smpF

i need to extract this data and store it into a database but within one cell, as each col represents either TN-TP-FP-FN i decided to number each data entry using this:

 [p,q]=size(MATRIX);                                     % Get dimensions of MATRIX
for j = 1:q                                             % Number of columns in MATRIX
    for i = 1:p                                         % Number of rows in MATRIX
        Temp = char(MATRIX(i,j));                       % Extract value at i,j
        if ~isempty(Temp)                         
            if (j == q && i == p && j ~= 1 && i ~= 1)
                    STRING = [STRING Temp int2str(j)];      % Last entry
                elseif (j == 1 && i == 1)
                    STRING = [Temp int2str(j) ','];         % First entry
                else
                    STRING = [STRING Temp int2str(j) ','];  % Other entries

            end

       end
    end
end
% Check for presence of last comma
if strcmp(STRING(end),',') == 1
    STRING=STRING(1:end-1);                               %Omit last character which could be comma
end

This works fine and gives something like smpA1,smpB2,smpE2,smpC3,smpF3,smpD4

however when there is a set of samples which were not used to generate data it obviously crashes

 col1---col2---col3---col4
       smpB           smpD
       smpE

I tried something like this:

 [p,q]=size(MATRIX);                                     % Get dimensions of MATRIX
for j = 1:q                                             % Number of columns in MATRIX
    for i = 1:p                                         % Number of rows in MATRIX
        Temp = char(MATRIX(i,j));                       % Extract value at i,j
        if ~isempty(Temp)                         
            if (j == q && i == p && j ~= 1 && i ~= 1)
                    STRING = [STRING Temp int2str(j)];      % Last entry
                elseif (j == 1 && i == 1)
                    STRING = [Temp int2str(j) ','];         % First entry
                else
                    STRING = [STRING Temp int2str(j) ','];  % Other entries

            end
         *  else isempty(Temp)
                  if (j == q && i == p && isempty(j) == 1 && isempty(i) ==1)
                  STRING = [STRING Temp ','];*
       end
    end
end

if strcmp(STRING(end),',') == 1 STRING=STRING(1:end-1); end

i get the following error

??? Undefined variable or function STRING might refer to the function string.

Error in ==> cellmatrix2string2 at 44 STRING = [STRING Temp int2str(j) ',']; % Other entries

anyone know why this is occuring, and a way around it?

Answer 1

[Image Analyst]

I didn't look over your algorithm in detail but it looks like you can define STRING in a way that requires an existing value for STRING:

STRING = [STRING Temp int2str(j)];

but I didn't see you initialize STRING. So maybe put

STRING = '';

at the beginning of your code.

[Gurvinder]

ah sorry i didnt upload the full part of the code, at the top of the function i have:

function STRING = cellmatrix2string2(MATRIX)