How can I read a specific line from a data file (.txt)?

How Can I read a specific line from a data file (.txt)?

Hi everyone,

simple problem :

I got a data file with a much lines (characters and numbers).

How can I read from the line 30 of the file (the line where appears "INACTIVE_LENGTH = 721.8400 " ?

I've just seen a lot of answers about this topic, but I didn't find a right answer for my problem.

Thanks for all !

Claudio

P.S. the data file in question is attached. Its original format is *.trk, but it's well readable by Notepad, Blocconote, etc.

Answer 1

[Walter iacomacci]

Hi Claudio this Question has been already answered before here: Read an Specific line from a .txt, I think you will find your solution there!.

You are welcome.

Walter A. Iacomacci

[Claudio Savito]

Thanks Walter,

I tried to run the code that you has suggested me, but it gives me errors.

I wrote:

% open the file

fid=fopen('E:\Claudio.cdb\tracks.tbl\MF011\F011_20.txt','r');

% set linenum to the desired line number that you want to import

linenum = 30;

% use '%s' if you want to read in the entire line or use '%f' if you want to read only the first numeric value

param1 = textscan(fid,'%s',1,'delimiter','\n', 'headerlines',linenum-1);

Matlab gives me in return fid = -1, and these errors:

Error using textscan

Invalid file identifier. Use fopen to generate a valid file identifier.

Error in Untitled2 (line 127)

param1 = textscan(fid,'%s',1,'delimiter','\n', 'headerlines',linenum-1);

Answer 2

[Claudio Savito]

Now, I tried:

% open the file

fid=fopen('E:\Claudio.cdb\tracks.tbl\MF011\MF011_20.txt','w','n');

%%

% set linenum to the desired line number that you want to import

linenum = 30;

% use '%s' if you want to read in the entire line or use '%f' if you want to read only the first numeric value

param1 = textscan(fid,'%s',1,'delimiter','\n', 'headerlines',linenum-1);

Now fopen works and gives me fid=-6, but it appears an error in textscan:

Error using textscan

Unable to read any data from the file. TEXTSCAN might not have read access.

Error in Untitled2 (line 131)

param1 = textscan(fid,'%s',1,'delimiter','\n', 'headerlines',linenum-1);