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How can I extract data from a table and put it into a new one?

Asked by Tessa Coenraad on 22 May 2019
Latest activity Answered by Peter Perkins
on 22 May 2019
Hi!
We made a loop to create a table where all our measurements can be put in. The problem is, that all the measurements are done 4 times(for 1 machine), and we want a new table with the four measurements (from one machine) put in seperate colums.
Our loop looks like this:
files=dir('*.log');
M=NaN(length(files),1);
Lek=M;
B=M;
C=M;
R=M;
PS=M;
TV=M;
For i=1:length(files)
out=textscan(files(i).name,'M%f_Lek%f_B%f_C%f_R%f_PS%f');
A = readcell(files(i).name); %data inladen
Z = string(A);
time = Z(7:end,1); %van time een vector maken
time = strrep(time, ',', '.'); %komma's in vector in punten veranderen
time = str2double(time);
flow = Z(7:end,2);
flow= strrep(flow, ',', '.');
flow = str2double(flow);
flow = flow./60;
flowpos = flow;
flow(flow<0)= 0;
RR=23;
volpos = trapz(time, flow);
TV(i)= (volpos./RR);
TV(i)= TV(i).*1000;
M(i)=out{1};
Lek(i)=out{2};
B(i)=out{3};
C(i)=out{4};
R(i)=out{5};
PS(i)=out{6};
end
T=table(M,Lek,B,C,R,PS,TV,'VariableNames',{'M','Lek','B','C','R','PS','TV'})
If M is 1, we want TV to be in column '1' of the new table, if M is 2, we want TV to be in column '2' of the new table, etc....
How can we do this?
We managed to create a new table just like above, but he wont fill in the TV's.
Thanks in advance, Tessa

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2 Answers

Answer by Luuk van Oosten on 22 May 2019
 Accepted Answer

Beste Tessa,
You almost wrote it yourself already, if I understand your problem correctly....? You already wrote in pseudocode a perfect example of an elseif statement when you said:
"If M is 1, we want TV to be in column '1' of the new table, if M is 2, we want TV to be in column '2' of the new table, etc...."
% so you have some kind of M, lets say M is 2
M = 2
if M==1
yourcodeforputtingitincolumn1ofthetable
elseif M ==2
yourcodeforputtingitincolumn2ofthetable
elseif M ==3
yourcodeforputtingitincolumn3ofthetable
elseif M == N
yourcodeforputtingitincolumnNofthetable
else
disp('back to the drawing board')
end
If this is not what you meant, please clarify.

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The problem is that we dont know how to write the code for putting it into the right column of a new table. Also i'm not sure if MATLAB "knows" it has to read out of the first table T....

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Answer by Peter Perkins
on 22 May 2019

With no example, it's hard to understand what you have and what you want to end up with, but your description sounds very much like you want to use unstack.

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