xsortrec.m

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%                             xsortrec.m
%  Scope:   This MATLAB program reads a data file (each row is a record), 
%           sorts the records by the elements of a specified column in 
%           ascending order, and writes the result into an external file.
%  Usage:   xsortrec
%  Inputs:  - name of the input file 
%           - index of the column used in ordering the records
%           - name of the output file (optional)
%  Outputs: - ordered data records on the specified file or on screen
%  Remarks:
%           The format of the output file should be changed to reflect 
%           the number and data types used in each record (the default is
%           for the structure used in file data2.dat).
%  Last update:  06/27/00
%  Copyright (C) 1998-00 by LL Consulting. All Rights Reserved.

clear  

yes = 'y';
disp(' ');

%  Read the input data file

f1 = input('Specify the input filename (with extension), e.g. data2.dat --> ','s');
disp(' ');

tt = load(f1);
[nrow,ncol] = size(tt);
z = zeros(nrow,ncol);
disp(['The input array ' f1 ' has ' num2str(ncol) ' columns']);
disp('  ');

%  Specify the column used to arrange the records in ascending order

kcol = input('Specify the column index used for sorting --> ');
disp(' ');

x = tt(:,kcol);

%  Sort the records by the value of the elements in selected column,
%  in ascending order

[y,index] = sort(x);

for k = 1:nrow
    z(k,:) = tt(index(k),:);
end

%  Save the generated data into a specified file if desired

answer2 = input('Do you want to save the generated data? (y/n)[y] --> ','s');
disp(' ');
if  isempty(answer2)
   answer2 = 'y';
end
if strcmp(answer2,yes) == 1
   f2 = input('Specify the output file name  --> ','s');
else
   f2 = 1;        %  output to the screen
end

%  Save results into an external file. The format of the output file
%  should be changed to reflect the number and data types used in
%  each record. The default is for the structure used in file data2.dat.

for k = 1:nrow
   fprintf(f2,'%d %12.7f %12.7f %8.0f  %d  %d  %14.7f \n',z(k,1:ncol));
end

disp('  ');
disp('End of the program  XSORTREC ');
disp('  ');