Building a matrix inside a for loop

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Murstoe
Murstoe 2020-5-15
评论： Rena Berman 2020-6-1
Hi guys, can anyone help me with this please. Thanks.
So i have this Excel file. I filtered a column and then did some operations on the filtered data .
in the end, I wanna create a new matix, A, with the following characteristics. The matrix should have dimension: partID rows* 5 columns. First colum should contain the partID number (from 3 to 15), second column should contain the value of M associated with the partID, third column S, fourth m and fifth s.
how do i build A inside the cycle?
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Murstoe
Murstoe 2020-5-23
Guys I’m so sorry I don’t know what happened to it. I will sure fix it. I apologise again

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Turlough Hughes
Turlough Hughes 2020-5-16
编辑：Turlough Hughes 2020-5-16
You could do it as follows:
xlsData = xlsread('PartS_all.xlsx');
partID = xlsData(:,4);
uPartID = unique(partID).'; % Unique part IDs
% Preallocate space
c = 0;
A = zeros(numel(uPartID),5);
for currPartID = uPartID
c = c+1;
part = xlsData(xlsData(:,4) == currPartID,:); %edit
A(c,:) = [currPartID mean(part(:,8)) std(part(:,8)) mean(part(:,11)) std(part(:,11))];
end
  2 个评论
Murstoe
Murstoe 2020-5-16
I get the following error:
Index in position 2 exceeds array bounds (must not exceed 1).
Error in Untitled (line 25)
A(c,:) = [currPartID mean(part(:,8)) std(part(:,8)) mean(part(:,11)) std(part(:,11))];
Turlough Hughes
Turlough Hughes 2020-5-16
I made a mistake. It should work fine now.

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