[SOLVED] How to read data file from a specific line ?

Hi all,

simple problem :

1. I got a data file in which 10 first lines are characters.
2. Then, from the line 11, there are only floats.
3. How can I read from the line 11 until the end of the file ?

Thanks for all !

Florian

Answer 1

[Salaheddin Hosseinzadeh]

Hi buddy

It's dead easy, I'm copy pasting part of a code I wrote to manipulate text files in which I read the text file line by line. anytime you us

   fid1=fopen('D:\Dale Jr.PLR','r'); % This opens a file
 fid2=fopen('F:\NEW_Dale Jr.PLR','r');
 line_num=0;
 l1='0';
 l2='0';
 while(ischar(l1)||ischar(l2)); % this continues until the end of file 
     line_num=line_num+1;
     l1=fgetl(fid1); % anytime you use fgetl you read a line and next time you use it reads next                        
     l2=fgetl(fid2);
     if(isequal(l1,l2)==0)
         disp(['L1=',l1])
         disp(['L2=',l2])
         line_num
         err(line_num)=line_num;
     end

 end

Ok in this program I checked the content of 2 files, wanted to make sure if they are the same. Ignore the program, what's important is to use fgetl ,I include some comment for you in the code, just wanna emphasis that first time you use fgetl, it reads the first line, next time you use it it will read the second line, so you don't have to have a counter for the lines, unless you want to save the lines like I did and I assigned a variable and a counter for the variable to save all the lines. Refer to MATLAB product help for more examples and information.

Good Luck!

[Florian]

Hi !

Thank you very much for your answer, it's really fine !

Solved, Florian

[Juan Espinosa]

Hi there,

Just for clarify, if someone just want to read the content of the file

 fileId=fopen('D:\MATLAB\Oscar\GUI\InterfaceC.m','r'); % This opens a file
 line_num=0;
 lineData='0'; 
 while ~feof(fileId)
     line_num=line_num+1;
     lineData=fgetl(fileId); % read a line     
     disp(['Line ',num2str(line_num) , ': ' lineData ]);
 end

Regards Juan

[Walter Roberson]

To display a file with line numbers, you can use dbtype

dbtype D:\MATLAB\Oscar\GUI\InterfaceC.m

[LS]

How can I save the output lines in a vector? I would like to access every single line by an index.

[Walter Roberson]

R2020b introduced readlines() https://www.mathworks.com/help/matlab/ref/readlines.html

For earlier releases,

LINES = regexp(fileread(FILENAME_GOES_HERE), '\r?\n', 'split');
if isempty(LINES{end}); LINES(end) = []; end  %end of file correction

[KAE]

@Walter Roberson - Can't vote up your readlines suggestion, but very helpful to learn about this.

Answer 2

[Walter Roberson]

See textscan with a HeaderLines parameter of 10

Note: you cannot use csvread() or dlmread() for this purpose.

Answer 3

[Mireia Fontanet]

Dear,

I have to txt files, one is called variables.txt and the other one is called selector.in.txt. I want to replaced the first line of variables.txt file with the second line of selector.in.txt. How can I do it?

Regards,

[Walter Roberson]

See https://www.mathworks.com/matlabcentral/answers/8801-replacing-and-inserting-a-text-in-an-ascii-file#comment_520585 as I answered in the other place you posted this. You should have just created a new Question.