在 Matlab 中：如何在多个数据文件中删除从第 xxx 行到文件末尾的行范围

Question

我有多个数据文件，有时我想删除其中不必要的额外数据行，例如从第 8000 行到最后一行。我想对 .txt 文件中包含的所有数据文件执行此操作。我以前是手动完成的，但经常这样做是一项乏味的工作。 我已经合并并修改了一些我在网上找到的代码，但我有两个问题：

1. 我不知道如何设置范围，这样代码将删除第8000行之后的所有行。直到数据结束因此我假设要删除的行数是一个很大的数字（1000） .但这不是一个好的解决方案，因为数据文件中的总行数可能超过 9000。
2. 第二件事是我无法复制或移动创建的临时文件，其中包含新数据而没有额外的行来替换原始文件:(我发现临时文件夹中的通用唯一标识符 (UUID) 是与“outfile”中的不一样，例如 Matlab 中 outfile 的 UUID 代码是 tp58460076_aaad_4621_b2ac_c7036febc3f0 而在临时文件夹中是 tp30ade3f8_3abc_4e00_a2ef_26d67c5f836e 我在 Matlab 中同时使用了 copyfile 和 movefile

如果有人有替代解决方案或知道此代码出了什么问题，请帮忙！

close all
clear
clc
% Specify the folder where the files live.
myFolder = 'C:\Users\Emma\Data';
% Check to make sure that folder actually exists.  Warn user if it doesn't.
if ~isdir(myFolder)
  errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
  uiwait(warndlg(errorMessage));
  return;
end
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(myFolder, '*.txt'); % Change to whatever pattern you need.
theFiles = dir(filePattern);

for k = 1 : length(theFiles)
  baseFileName = theFiles(k).name;
  fullFileName = fullfile(myFolder, baseFileName);
  fprintf(1, 'Now reading %s\n', fullFileName);
%*****************************
first_line_to_delete = 8003;
num_lines_to_delete = 1000;
infilename = fullFileName;
[pathstr, file, ext] = fileparts(infilename);
backfile = fullfile(pathstr, [file '.bak']);
if strcmp(infilename, backfile)
  error('I refuse to edit a backup file! Nothing has been changed.');
end

outfile = tempname;   %a temporary file in TMP directory
fin = fopen(infilename, 'r');
if fin < 0; error('Input file does not exist'); end 
fout = fopen(tempname, 'w');
if fout < 0
  fclose(fin);
  error('Could not open temporary output file');
end

%read lines before the one to be deleted and write them to output
for K = 1 : first_line_to_delete - 1;
  inline = fgets(fin);
  if ~ischar(inline); break; end;  %end of file?
  fwrite(fout, inline);
end
for K = 1 : num_lines_to_delete;
  if ~ischar(inline); break; end   %in case EOF
  inline = fgets(fin);   %and do nothing with it
end
%copy all remaining input lines to output file
while ischar(inline)
  inline = fgets(fin);
  if ischar(inline)   %not if we hit EOF
    fwrite(fout, inline);
  end
end
fclose(fin);
fclose(fout);

%we did the copying and have a file with the desired
%result. Now put it in the proper place
[status,message,messageId]  = copyfile(infilename, backfile, 'f'); %Emma mod
if ~status
  if strcmp(infilename, backfile)
    fprintf(2, 'Good thing your programmer is paranoid about people overriding\nsanity checks, because something went wrong and you nearly lost your file!\n');
  else
    delete(backfile);
  end
  error('Could not rename file to .bak, file left untouched');
else
  [status,message,messageId]  = copyfile(fullfile(outfile, [myFolder, infilename]), 'f');
  if ~status
    error( ['Could not rename temp file to original name, original moved to ', backfile]);
  end
end
%**************************
end

Answer 1

这个问题的答案是以下命令：

sed -i '8003,$ d' *.txt