MATLAB: Unique command and external Excel files

excel columnsMATLABunique

I have 50 EXCEL files. In Sheet 2 of each EXCEL file, there are mainly two columns called WA and CI. The program below should take these two columns and check if there are repeated values. I have attached one of the typical Excel files on here. The file is indexed 2.xlsx. The program has a for-loop on external files. The strange thing is that MATLAB says that CI has a repeated value but, checking the file, there is no repetition. If I copy the column CI in MATLAB. I execute the command length(CI) == length(unique(CI)). Then the result is 1. There are no repetead values. This corresponds to the truth because there are no repeated values in CI. I do not understand where I am wrong in this small program and why the two outcomes are different.

path_to_folder = '~/Desktop/75_3/';
for i=1:50
  file = strcat(num2str(i),'.xlsx');
  path_to_file = strcat(path_to_folder,file);
  subset = xlsread(path_to_file,'Sheet2');
 CI = subset(:,2);
  length(CI) == length(unique(CI))
 end

Best Answer

Well, there is a duplicate in the 2nd column...

>> d=xlsread('x.xlsx','Sheet2');
>> arrayfun(@(i)numel(unique(d(:,i)))==numel(d(:,i)),[1:2])
ans =
  1×2 logical array
   1   0
>> 
> sd=sort(d(:,2));
>> find(diff(sd)==0)
ans =
    71
>> sd(70:72)
ans =
   0.759021496168829
   0.765957446808511
   0.765957446808511
>> [u,iu]=unique(d(:,2));
>> whos u
  Name       Size            Bytes  Class     Attributes
  u         74x1               592  double              
>>

Related Solutions

MATLAB: Read multiple excel file and write into single excel file

hello

you can try this.

 source_dir = 'C:\Users\sourcedir.....' %my file source dir
 dest_dir = 'C:\Users\destdir.......'  %my file dest dir
 source_files = dir(fullfile(source_dir, '*.xls'));
 data = zeros(100,20)
 for i = 1:length(source_files)
     data(i,:) = xlsread(fullfile(source_dir, source_files(i).name));
     %or to make sure you only read one line
     %data(i,:) = xlsread(fullfile(source_dir, source_files(i).name),1,'A1:T1');
 end
 xlswrite('finalthermo.xls',data);

MATLAB: Store vectors from a for loop in a matrix

You can use the following pattern when you are using a for loop over a range of non-integral values:

 ci_vals = 0.0001:0.5:(2*alt_Col);
 num_ci = length(ci_vals);
 num_di = length(di);
 Esi = zeros(num_ci, num_di);
 for ci_idx = 1 : num_ci;
    ci = ci_vals(ci_idx);
    Esi(ci_idx, :) = 0.003*((ci-di) ./ (ci)); 
 end

... Or you could omit the for loop, and use a vectorized approach:

ci = 0.0001:0.5:(2*alt_Col);
Esi = 0.003 * bsxfun(@rdivide, bsxfun(@minus, ci, di), (ci));

Or you could use:

ci = 0.0001:0.5:(2*alt_Col);
[CI, DI] = meshgrid(ci, di);
Esi =  0.003 * ((CI-DI) ./ (CI));

or, in R2016b or later, you can use built-in implicit expansion:

ci = 0.0001:0.5:(2*alt_Col);
Esi = 0.003 * ((ci-di) ./ (ci));

The bxsfun version is a more efficient approach than meshgrid. The implicit expansion version "aims" to be more efficient than the bsxfun but user tests have shown that sometimes the implicit expansion version is slower than the bsxfun version.

Best Answer

Related Solutions

MATLAB: Read multiple excel file and write into single excel file

MATLAB: Store vectors from a for loop in a matrix

Related Question