Load in multiple text files and store data in a matrix

Question

Benjamin Cowen 2018-8-16

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/415189-load-in-multiple-text-files-and-store-data-in-a-matrix

编辑： Walter Roberson 2018-12-5

I have 28 text files, of this pattern:

 out.200.data
 out.225.data

up to

out.900.data

How can I populate the 3rd row into a matrix? Note that there are 3 columns in the 3rd row. I also have a path to my files, but for purposes here, let's just say the path is just C:/Path

Is there a way to create a single matrix with these values?

Row 1 of the matrix is the 3rd row of out.200.data
Row 2 of the matrix is the 3rd row of out.225.data

etc?

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TAB 2018-8-17

What is format of your data in text file?

Benjamin Cowen 2018-8-17

编辑：Walter Roberson 2018-8-17

2 header rows

3rd row is 3 numbers, separated by spaces

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Answer 1

Walter Roberson 2018-8-17

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/415189-load-in-multiple-text-files-and-store-data-in-a-matrix#answer_333075

在 MATLAB Online 中打开

http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

for information on looping over files.

For any one file, I suggest something like

   filename = fullfile(projectdirectory, dinfo(K).name);
   fid = fopen(filename, 'rt');
   row3(K,:) = cell2mat( textscan(fid, '%f%f%f', 1, 'headerlines', 2, 'collectoutput', true) );
   fclose(fid)

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Benjamin Cowen 2018-8-17

编辑：Benjamin Cowen 2018-8-17

在 MATLAB Online 中打开

@Walter Roberson Thanks for this, it worked. If I only have 1 headerline, I want to extract the 51st row, and there are only 2 columns as opposed to 3, why does this not work:

clear
clear all
clc
projectdirectory = 'C:/Path/';
dinfo = dir( fullfile(projectdirectory, 'msd.*.data') );
N = length(dinfo);
row51 = zeros(N, 2);
for K = 1 : N
  filename = fullfile(projectdirectory, dinfo(K).name);
  fid = fopen(filename, 'rt');
  row51(K,:) = cell2mat( textscan(fid, '%f%f', 50, 'headerlines', 1, 'collectoutput', true) );
  fclose(fid);
end

Walter Roberson 2018-8-17

编辑：Walter Roberson 2018-12-5

在 MATLAB Online 中打开

clear
%let us refrain from blowing up the bridge we are standing on, like Wile E. Coyote
%<<https://cdn-images-1.medium.com/max/1338/1*8oK7yw-tYvP14l_Ya3Nvcg.png>>
%clear all
clc
Row_to_extract = 51;
projectdirectory = 'C:/Path/';
dinfo = dir( fullfile(projectdirectory, 'msd.*.data') );
N = length(dinfo);
row = zeros(N, 2);
for K = 1 : N
  filename = fullfile(projectdirectory, dinfo(K).name);
  fid = fopen(filename, 'rt');
  row(K,:) = cell2mat( textscan(fid, '%f%f', 1, 'headerlines', Row_to_extract - 1, 'collectoutput', true) );
  fclose(fid);
end