reading header line from text file

Hi,

I have text file with 2 header lines and data (7 columns). I can read the data using textscan, but not able to read header file (using fgets). Please see the code below:

fid = fopen(files(1).name, 'rt'); 

C = textscan(fid, '%f %f %f %f %f %f %f' ,'HeaderLines',2,'Delimiter',',');

tline = fgets(fid);

fclose(fid);

It gave tline = -1.

Any help regarding the problem, will be really appreciated. Thanks, Rami

[Rami]

Hi,

I able to resolve the problem with writing fgets first and then textscan:

fid = fopen(files(1).name, 'rt'); 

tline = fgets(fid);disp(tline)

C = textscan(fid, '%f %f %f %f %f %f %f ' ,'HeaderLines',2,'Delimiter',',');

fclose(fid);

But now I run to another problem, how can I read the particular text from header line. For example, from header line below, I want to read number:

[Number, time(16215.00), x, y, z]

Thanks, Rami

Answer 1

[José-Luis]

It means the position indicator is not at the beginning of the file after it exits textscan:

You can either rewind:

 fid = fopen(files(1).name, 'rt'); 
 C = textscan(fid, '%f %f %f %f %f %f %f' ,'HeaderLines',2,'Delimiter',',');
 frewind(fid);
 tline = fgets(fid);
 fclose(fid);

Or read it first:

 fid = fopen(files(1).name, 'rt'); 
 line1 = fgets(fid);
 line2 = fgets(fid);
 C = textscan(fid, '%f %f %f %f %f %f %f' ,'Delimiter',',');
 tline = fgets(fid);
 fclose(fid);

[Rami]

Hi,

As you suggested, I able to resolve the problem with writing fgets first and then textscan:

fid = fopen(files(1).name, 'rt'); 

tline = fgets(fid);disp(tline)

C = textscan(fid, '%f %f %f %f %f %f %f' ,'HeaderLines',2,'Delimiter',',');

fclose(fid);

But now I run to another problem, how can I read the particular text from header line. For example, from header line below, I want to read number only:

[Number, time(16215.00), x, y, z]

Thanks, Rami

[Jan]

Use a matching SSCANF command.

To read two header lines, you need two FGETS commands. Afterwards TEXTSCAN should not skip the header lines again, because this would ignore two lines of data.

[Rami]

Thanks Jan,

Your comment was useful for me. However I was not able to make work SSCANF, but STRFIND and STR2DOUBLE.

Thanks for taking time to help. Rami

[Dr. Seis]

If you always have the same "somethings" then you may be able to do something like this:

headerline = '[something,something(546231122.23),x,y,z]';
number = sscanf(headerline,'[something,something(%f),x,y,z]');

[Rami]

Thanks Elige,

That was an elegant way to get the number.

Rami

Answer 2

[Gabriel Felix]

I had to use \n at the end of each line. Without it I couldn't make textscan() work properly, even thoug the "HeaderLines" was configured according to the text file lines. This was the only solution I found after struggling with the code for an intire day.

This was the text:

!
!
! alfa (graus) =  5.0
!
! Id.      x/s       z/s     alfai       cl     c*cl/cmed    cdi      cmc/4
!                           (graus)
   1      .246      .050    -1.209      .255      .332     .00538     .0170
   2      .292      .150    -1.098      .259      .319     .00496     .0545
   3      .339      .250     -.925      .254      .297     .00410     .0944
   4      .385      .350     -.741      .243      .268     .00315     .1341
   5      .432      .450     -.561      .227      .235     .00223     .1714
   6      .479      .550     -.393      .206      .199     .00141     .2034
   7      .525      .650     -.238      .181      .163     .00075     .2266
   8      .572      .750     -.101      .152      .126     .00027     .2362
   9      .619      .850      .014      .116      .089    -.00003     .2236
  10      .659      .938      .103      .074      .052    -.00013     .1693
!
! CL asa    =  .208
! CDi asa   =  .00258
! e (%)     =  88.9
! CMc/4 asa =  .1339

My code:

%! alfa (graus) =  5.0
P = textscan(fid,'! alfa (graus) = %f','Delimiter',' ','MultipleDelimsAsOne',true,'headerLines',2,'CollectOutput',1);
alpha(1) = P{1};
%! CL asa    =  .208
P = textscan(fid,'! CL asa = %f\n','Delimiter',' ','MultipleDelimsAsOne',true,'CollectOutput',1,'headerLines',4+n);
CL(1) = P{1};
%! CDi asa   =  .00258
P = textscan(fid,'! CDi asa   =  %f\n','Delimiter',' ','MultipleDelimsAsOne',true,'CollectOutput',1,'headerlines',0);
CDi(1) = P{1};
%! CMc/4 asa =  .1339
P = textscan(fid,'! CMc/4 asa = %f','Delimiter',' ','MultipleDelimsAsOne',true,'CollectOutput',1,'HeaderLines',2);
Cmc4(1) = P{1};