How to use imported data with trapz( )

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Johana Aguero-Fischer
Johana Aguero-Fischer on 19 Sep 2022
Answered: KSSV on 20 Sep 2022
Hi, I have imported two columns of a csv data file into Matlab and are contained in one table. The columns are labeled Times and DragForceN. I want to use them in trapz(x,y). My end goal here is to obtain the work done by drag. I keep getting an error message and I cannot figure out how to fix it. Any help would be appreciated.
x = importdata('Times.csv');
y = importdata('DragForceN');
dragWork_H13 = trapz(x,y)
  4 Comments
dpb
dpb on 19 Sep 2022
Well, the error says importdata couldn't open the file; you didn't even get to the second step...it didn't say it couldn't find the file; so apparently there is such a file but it wasn't a valid text file as the .csv extension would suggest it should be.
But, we can't tell what went wrong -- attach the file so somebody can try to duplicate the issue/see what the file really does contain.
Johana Aguero-Fischer
Johana Aguero-Fischer on 19 Sep 2022
I have attached the csv file I imported into MATLAB. I only run the values of Time and Drag up to Apogee which is up to time=10.7 seconds

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Answers (1)

KSSV
KSSV on 20 Sep 2022
T = readtable('https://in.mathworks.com/matlabcentral/answers/uploaded_files/1129920/H182%20Drag.csv') ;
Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.
x = T.(1) ;
y = T.(2) ;
% fill the NaN's in the data
x = fillmissing(x,'linear') ;
y = fillmissing(y,'linear') ;
%
trapz(x,y)
ans = 122.9553

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