How to identify text files with zero value

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Tanmoyee Bhattacharya 2023-4-17

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评论： dpb 2023-4-19

采纳的回答： dpb

I have 10 text files and each text file has 9 rows and one column. In some text file total column is zero. Like

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In other file there are zero values and numbers. Like

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I want to extract text files with total column of zero values

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If there is any way to extract the text files

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Answer 1

dpb 2023-4-17

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移动：dpb 2023-4-17

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"...is any way to extract the text files[?]"

What do you mean by "extract", precisely? What is the end result you're after; to read the data files that actually contain one or more nonzero values, identify which files are those that contain only zero values, ...?

The answer to all of those will be based on simply reading each file in turn and testing the content something like

d=dir('*.txt');     % substitute suitable wildcard for your case to identify wanted files
for i=1:numel(d)
  data=readmatrix(fullfile(d(i).folder,d(i).name));
  if any(data)
    %...do what need to do for those with some nonzero values here
  else
    %...and all zeros here...
  end
end

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dpb 2023-4-19

编辑：dpb 2023-4-19

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That's a pretty old release by now, but dir() predates it so that isn't the problem. But, without the full error message in context with the exact code you ran, we can't really say anything except that it, alone, would be ok(*). That, of course, implies that your code got far enough along to have created the dir() structure and the reference isn't to some other pre-existing variable that isn't the output of a call to the function. We simply can't see/tell without context...

(*) Of course, your directory search may not have returned any results, but dir() will return an empty struct in that case; the struct names will still exist; there just won't be any content. Hence, that isn't the cause of the error message, either.

But, when you resolve that, then readmatrix will fail because it wasn't introduced until R2019a; you'll have to revert to one of the earlier forms to input the data file; see textread for a way that approximates what readmatrix would have done that also takes the file name rather than needing to open/close a file handle.

data=textread(d(i).folder,d(i).name,'%f');

would work if the data in the files does consist of just the one column; now you'll have to be much more aware of the actual file structure; most of the more user-friendly higher-level functions that attempt to remove the need to delve into the file structure itself postdate your release.

Walter Roberson 2023-4-19

编辑：Walter Roberson 2023-4-19

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Old enough versions of MATLAB did not have the .folder property of dir() results.

%the below logic requires that the data file be just a list of numbers,
%one per line, with no headers. (Or if it has headers, the header line must
%start with '%' characters.)
%if this is not true, if there are header lines, the code would need to be
%modified
folder_to_search = 'C:\Users\DELL\Desktop\file';
folder_to_move_allzero = './all0';
folder_to_move_rest = './not0';
if ~isdir(folder_to_move_allzero); mkdir(folder_to_move_allzero); end
if ~isdir(folder_to_move_rest); mkdir(folder_to_move_rest); end
d = dir( fullfile(folder_to_search, '*.txt'));     % substitute suitable wildcard for your case to identify wanted files
for i=1:numel(d)
  thisfile = fullfile(folder_to_search,d(i).name);
  data = load(thisfile, '-ascii');
  if any(data)
    movefile(thisfile, folder_to_move_rest);
  else
    movefile(thisfile, folder_to_move_allzero);
  end
end