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

3 次查看（过去 30 天）
Claudio Savito
Claudio Savito 2019-10-19
回答： Claudio Savito 2019-10-26
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.

请先登录，再回答此问题。

回答（2 个）

Walter iacomacci
Walter iacomacci 2019-10-19
编辑：Walter iacomacci 2019-10-19
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
  1 个评论
Claudio Savito
Claudio Savito 2019-10-26
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);

请先登录，再进行评论。

Claudio Savito
Claudio Savito 2019-10-26
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);

类别

在 Help Center 和 File Exchange 中查找有关 Workspace Variables and MAT Files 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by