[Eeglablist] How to get the largest-contributing components at a specified frequency manually

[nastaran.takmil at st.ovgu.de]

Hello everyone,
In order to get the largest-contributing components at a specified  
frequency, I followed this path:
eeglab->Plot->Component spectra and maps

I got the plot of the largest-contributing components (I have attached  
the figure) and also all components percent relative variance at the  
chosen frequency were printed on the command window.
Since I want to do the same thing for many participants, I was  
thinking of writing a code which can give me the components percent  
relative variance at a specified frequency as an output.
I tried to use the main eeglab codes such as pop_spectopo and spectopo  
to understand how to get those components percent relative variance as  
a separate output but what I can see in the output generation part of  
pop_spectopo.m is:

% plot the data and generate output and history commands
% ------------------------------------------------------
popcom = sprintf('figure; pop_spectopo(%s, %d, [%s], ''%s'' %s);',  
inputname(1), dataflag, num2str(timerange), processflag, options);
switch processflag
	case { 'EEG' 'eeg' }, SIGTMP = reshape(SIGTMP, size(SIGTMP,1),  
size(SIGTMP,2)*size(SIGTMP,3));
	        com = sprintf('%s spectopo( SIGTMP, totsiz, EEG.srate %s);',  
outstr, spectopooptions);
                 eval(com)
        case { 'ERP' 'erp' },
                 com = sprintf('%s spectopo( mean(SIGTMP,3), totsiz,  
EEG.srate %s);', outstr,spectopooptions);
                 eval(com)
        case { 'BOTH' 'both' }, sbplot(2,1,1); com = sprintf('%s  
spectopo( mean(SIGTMP,3), totsiz,EEG.srate,''title'',''ERP'' %s);',  
outstr, spectopooptions);
                 eval(com)
	        SIGTMP = reshape(SIGTMP, size(SIGTMP,1),  
size(SIGTMP,2)*size(SIGTMP,3));
	        sbplot(2,1,2); com = sprintf('%s spectopo( SIGTMP, totsiz,  
EEG.srate, ''title'', ''EEG'' %s);', outstr, spectopooptions); eval(com)
end;

if nargout < 2 & nargin < 3
	varargout{1} = popcom;
end;
I don't know how the get output out of the strings printing the  
results! Has anyone tried coding like this before?
Could you please help me in sorting this out?
Nastaran