MATLAB Answers

FOR loop through multiple datasets

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Elizabeth Yeap
Elizabeth Yeap on 9 Dec 2019
Edited: Elizabeth Yeap on 10 Dec 2019
I want to create a for loop that will sum specific columns of a single row of a matrix in a dataset. I then want to repeat that action for other datasets. The matrix is 37 rows x 100 columns. All datasets are from one mat. file.
% For Nubian Aquifer - 1900-1999
sum_ET = sum(aq_gwdctr_ET(1,:))/100;
sum_P = sum(aq_gwdctr_P(1,:))/100;
sum_R = sum(aq_gwd_qover(1,:))/100;
sum_dSdt = sum(aq_gwdctr_dSdt(1,:))/100;
sum_C = sum(aq_gwdctr_C(1,:))/100;
sum_GWpumping = sum(aq_irri4d(1,:))/100;
% For Nubian Aquifer - 1950-1999
sum_ET1 = sum(aq_gwdctr_ET(1,51:end))/50;
sum_P1 = sum(aq_gwdctr_P(1,51:end))/50;
sum_R1 = sum(aq_gwd_qover(1,51:end))/50;
sum_dSdt1 = sum(aq_gwdctr_dSdt(1,51:end))/50;
sum_C1 = sum(aq_gwdctr_C(1,51:end))/50;
sum_GWpumping1 = sum(aq_irri4d(1,51:end))/50;
% For Nubian Aquifer - 1900-1949
sum_ET2 = sum(aq_gwdctr_ET(1,1:50))/50;
sum_P2 = sum(aq_gwdctr_P(1,1:50))/50;
sum_R2 = sum(aq_gwd_qover(1,1:50))/50;
sum_dSdt2 = sum(aq_gwdctr_dSdt(1,1:50))/50;
sum_C2 = sum(aq_gwdctr_C(1,1:50))/50;
sum_GWpumping2 = sum(aq_irri4d(1,1:50))/50;
Currently, the code that I have performs all these individually. What I'm hoping to achieve is to simplify the above code. The new code should be able to;
A) For 1900-1999, sum all the columns for every row for each matrix, dataset. For 1950-1999, sum columns 51 until end for every row for each matrix, dataset. For 1900-1949, sum columns 1 until 50 for every row for each matrix, dataset.
B) This action should be repeated for each dataset (aq_gwdctr_ET, aq_gwdctr_P, etc.).
C) It would be a bonus if I could tabulate all these values.
% For year 1900-1999
Aquifer = [1; 2; 3]; % This is the rows in the matrix
ET = [sum_ET]; % Sum ET for each row in the matrix, repeat for each dataset
T = table(Aquifer, ET);
Thank you for your help.


Elizabeth Yeap
Elizabeth Yeap on 10 Dec 2019
@Walter, the mat files in the link that you posted are sequentially numbered which is not the case for my mat files. How would I change the example to fit my case?
Walter Roberson
Walter Roberson on 10 Dec 2019
projectdir = 'name of directory files are in';
fileext = 'mat';
dinfo = dir(fullfile( projectdir, ['*.' fileext] ));
filenames = fullfile(projectdir, {});
numfiles = length(filenames);
T = cell(1, numfiles);
for K = 1 : numfiles
thisfile = filenames{K};
[~, basename, ~] = fileparts(thisfile);
at this point analyze basename to figure out what year the file is for
at this point do whatever to load thisfile data
if file_year <= 1949
columns = 1:50;
columns = 51:size(aq_gwdctr_ET,2);
now analyze using columns as index
T{K} = table(Aquifer, ET);

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