How to extract specific rows from a text file?

% Parameter:
FileName = 'C:\HP1.txt';
Key      = '                   MODE             ';
NewFile  = 'C:\HP1_ordered.txt';
% Import text file and select lines starting with the Key string:
Str   = fileread(FileName);
CStr  = strsplit(Str, '\n');
Match = strncmp(CStr, Key, length(Key));
CStr  = CStr(Match);
% Create new file and write matching lines:
fid = fopen(NewFile, 'w');
if fid == -1
  error('Cannot create new file: %s', NewFile);
end
fprintf(fid, '%s\n', CStr{:});
fclose(fid);		

Hello,

I used this script to extract rows with a specific start, and now I need to extract from this last file in attachment only a series of rows with a specific index (for example I want only a row every 10 rows).

Can you help me?

Thanks,

Alberto

Answer 1

[infinity]

Hello,

Here is an solution that you can refer,

clear

FileName = 'HP1_ordered.txt';
NewFile = 'HP1_ordered_skip10.txt';

fp = fopen(FileName);
Str   = textscan(fp,'%s','delimiter',sprintf('\f'));
fclose(fp);

cStr = char(Str{1}(1:10:end)); % you can change number of row 
                                % that you want to skip at this line. 

fid = fopen(NewFile, 'w');
if fid == -1
  error('Cannot create new file: %s', NewFile);
end

for i = 1:size(cStr,1)
fprintf(fid, '%s\n', cStr(i,:));
end
fclose(fid);

In this code, it is supposed that you have "FileName" and want to write its containts into "NewFile". Also, you want to skip 10 rows of the "FileName".

Hope it could help.

[Orazio Alberto Terracciano]

Thank you very much, it works!