At every nth line read n lines together

time,n0v_soma,n1v_soma,n2v_soma,n3v_dend

0,-70,-70,-66.5,-66.5

0.027,-69.9703,-69.9794,-66.4966,-66.4966

0.054,-69.9685,-69.9533,-66.4933,-66.4933

0.081,-69.9283,-69.9322,-66.49,-66.4899

0.108,-69.9588,-69.9385,-66.4866,-66.4866

0.135,-69.9422,-69.8965,-66.4833,-66.4833

0.162,-69.9058,-69.8943,-66.48,-66.48

0.189,-69.8465,-69.8618,-66.4767,-66.4766

0.216,-69.8505,-69.8258,-66.4734,-66.4733

0.243,-69.7855,-69.8011,-66.4701,-66.47

0.27,-69.7913,-69.7594,-66.4668,-66.4667

0.297,-69.7228,-69.7291,-66.4636,-66.4634

0.324,-69.6841,-69.7006,-66.4603,-66.4601

0.351,-69.6907,-69.7157,-66.4571,-66.4569

0.378,-69.6584,-69.7295,-66.4538,-66.4536

0.405,-69.5766,-69.7279,-66.4506,-66.4503

0.432,-69.5668,-69.6756,-66.4474,-66.447

0.459,-69.5396,-69.6777,-66.4442,-66.4437

0.486,-69.511,-69.6717,-66.441,-66.4404

0.513,-69.4808,-69.6523,-66.4378,-66.4371

0.54,-69.4632,-69.6325,-66.4346,-66.4339

0.567,-69.4605,-69.6169,-66.4314,-66.4306

0.594,-69.4398,-69.6346,-66.4282,-66.4273

0.621,-69.4638,-69.6245,-66.4251,-66.424

0.648,-69.4429,-69.5968,-66.4219,-66.4207

0.675,-69.4134,-69.5639,-66.4187,-66.4174

0.702,-69.3973,-69.5655,-66.4156,-66.4141

0.729,-69.3973,-69.5668,-66.4125,-66.4108

0.756,-69.3611,-69.6189,-66.4093,-66.4075

My file looks something like this. I want to jump to every 10th line in the file and take that line and following 2 lines and then jump to the 10th line and do so forth and so on E.g The output should be like this

0.216,-69.8505,-69.8258,-66.4734,-66.4733

0.243,-69.7855,-69.8011,-66.4701,-66.47

0.27,-69.7913,-69.7594,-66.4668,-66.4667

0.486,-69.511,-69.6717,-66.441,-66.4404

0.513,-69.4808,-69.6523,-66.4378,-66.4371

0.54,-69.4632,-69.6325,-66.4346,-66.4339

I don't want to read by looping

Answer 1

[Walter Roberson]

per_line = 5;
every_nth_line = 10;
read_in_a_row = 3;

fmt = [repmat('%*f', 1, per_line*(every_nth_line-read_in_a_row)), repmat('%f', 1, per_line*read_in_a_row)];

fid = fopen('YourFile.txt', 'rt');

datacell = textscan(fid, fmt, 'delimiter', ',\n', 'HeaderLines', read_in_a_row-1, 'CollectOutput', 1);
fclose(fid);

C = reshape(datacell{1}.', per_line, []).';

With the data you posted, the result would be

     0.216   -69.8505   -69.8258   -66.4734   -66.4733
     0.243   -69.7855   -69.8011   -66.4701     -66.47
      0.27   -69.7913   -69.7594   -66.4668   -66.4667
     0.486    -69.511   -69.6717    -66.441   -66.4404
     0.513   -69.4808   -69.6523   -66.4378   -66.4371
      0.54   -69.4632   -69.6325   -66.4346   -66.4339
     0.756   -69.3611   -69.6189   -66.4093   -66.4075
       NaN        NaN        NaN        NaN        NaN
       NaN        NaN        NaN        NaN        NaN

The NaN are from the missing two lines after the 30th line that starts with 0.756, which you omitted from your output

[Shivik Garg]

Thank you Walter for your help. This code works.

Answer 2

[Azzi Abdelmalek]

You can't do it without a for loop unless you read all the file, then select the lines you want

Answer 3

[Shameer Parmar]

Hello Shivik,

Here is the Logic..

let us consider you have abc.txt file which is having these data.. So apply following logic and you will get the expected results.. Make sure that the abc.txt file is present in current directory of your working folder..

Data = textread('abc.txt', '%s', 'delimiter', '');
countNew = 1;
for count = 10:10:length(Data)
    NewData(countNew,1) = Data(count);
    if count+1 <= length(Data)
       NewData(countNew+1,1) = Data(count+1);
    end
    if count+2 <= length(Data)
       NewData(countNew+2,1) = Data(count+2);
    end
    countNew = countNew+3;
end

then type "NewData" and output will be :

 NewData = 

    '0.216,-69.8505,-69.8258,-66.4734,-66.4733'
    '0.243,-69.7855,-69.8011,-66.4701,-66.47'
    '0.27,-69.7913,-69.7594,-66.4668,-66.4667'
    '0.486,-69.511,-69.6717,-66.441,-66.4404'
    '0.513,-69.4808,-69.6523,-66.4378,-66.4371'
    '0.54,-69.4632,-69.6325,-66.4346,-66.4339'
    '0.756,-69.3611,-69.6189,-66.4093,-66.4075'