Dynamic Output Arguments in for-loop - matlab

Question

I am fairly new to Matlab and I created this script to help me gather 4 numbers out of an excel file. This one works so far:
clear all
cd('F:/Wortpaare Analyse/Excel')
VPNumber = input('Which Participant Number?', 's');
filename = (['PAL_',VPNumber,'_Gain_Loss.xlsx']);
sheet = 1;
x1Range = 'N324';
GainBlock1 = xlsread(filename,sheet,x1Range);
x1Range = 'O324';
LossBlock1 = xlsread(filename,sheet,x1Range);
x1Range = 'AD324';
GainBlock2 = xlsread(filename,sheet,x1Range);
x1Range = 'AE324';
LossBlock2 = xlsread(filename,sheet,x1Range);
AnalyseProband = [GainBlock1, LossBlock1, GainBlock2, GainBlock2]
Now I would like to make a script that will analyze the first 20 excel files and tried this:
clear all
cd('F:/Wortpaare Analyse/Excel')
for VPNumber = 1:20 %for the 20 files
a = (['PAL_%d_Gain_Loss.xlsx']);
filename = sprintf(a, VPNumber) % specifies the name of the file
sheet = 1;
x1Range = 'N324';
(['GainBlock1_',VPNummer]) = xlsread(filename,sheet,x1Range);
....
end
The problem seems to be that I can only have one output argument. I would like to change the output argument in each loop, so it doesn't overwrite "GainBlock1" in every cycle.
In the end I would like to have these variables:
GainBlock1_1 (for the first excel sheet)
GainBlock1_2 (for the second excel sheet)
...
GainBlock1_20 (for the 20th excel sheet)
Is there a clever way to do that? I was able to write the first script fairly easily, but was unable to produce any significant progress in the second script. Any help is greatly appreciated.
Best,
Luca

Answer 1

This can be accomplished by either storing the data in an array or a cell. I believe an array will be sufficient for what you're trying to do. I've included a re-organized code sample below, broken out into functions to help make it easier to read and understand.
Basically, the first function handles the loop and controls where the data gets placed in the array, and the second function is your original script which accepts the VPNumber as an input.
What this should return is a 20x4 array, where the first index controls the sheet the data was pulled from and the second index controls whether it's [GainBlock1, LossBlock1, GainBlock2, LossBlock2]. i.e.- GainBlock 1 for sheet 5 would be AnalseProband(5,1), LossBlock2 for sheet 11 would be AnalyseProband(11,4).
function AnalyseProband = getAllProbands()
currentDir = pwd;
returnToOriginalDir = onCleanup(#()cd(currentDir));
cd('F:/Wortpaare Analyse/Excel')
numProbands = 20;
AnalyseProband = zeros(numProbands,4);
for n = 1:numProbands
AnalyseProband(n,:) = getBlockInfoFromXLS(n);
end
end
function AnalyseProband = getBlockInfoFromXLS(VPNumber)
a = 'PAL_%d_Gain_Loss.xlsx';
filename = sprintf(a, VPNumber); % specifies the name of the file
sheet = 1;
x1Range = 'N324';
GainBlock1 = xlsread(filename,sheet,x1Range);
x1Range = 'O324';
LossBlock1 = xlsread(filename,sheet,x1Range);
x1Range = 'AD324';
GainBlock2 = xlsread(filename,sheet,x1Range);
x1Range = 'AE324';
LossBlock2 = xlsread(filename,sheet,x1Range);
AnalyseProband = [GainBlock1, LossBlock1, GainBlock2, LossBlock2];
end