MATLAB Central Newsreader - problems using textread

problems using textread

Matthew — Tue, 18 Nov 2008 20:48:02 -0500

i am trying to read in the 3rd value of the 1st numerical line 0.000 0.6149 0.00834 ........ of the file below using textread. however i am having a lot of problems and it just will not read the line i want. it is the first time i have used this type of text scanning read in method and it is starting to annoy me. i want to read the value in exactly as is shown in the file below then assign it to the variable Cd.

       XFOIL Version 6.94

Calculated polar for: test airfoil

1 1 Reynolds number fixed Mach number fixed

xtrf = 0.500 (top) 0.500 (bottom)
Mach = 0.100 Re = 1.000 e 6 Ncrit = 9.000

  alpha CL CD CDp CM Top_Xtr Bot_Xtr
------- -------- --------- --------- -------- ------- -------
   0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
   0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
   0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
   0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
   0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
   0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
   0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
   0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997

any help on this matter who be greatly appreciated as it does not seem to matter how i construct my code i just cannot get it to work :(

Re: problems using textread

Vadim Teverovsky — Tue, 18 Nov 2008 20:56:12 -0500

Two suggestions:
1) Use textscan instead of textread, it is the newer more full-featured
function.
2) Please post your code, otherwise its difficult to help. You likely need
to skip some number of headerlines, and then should be able to read the
numeric data.
"Matthew " <men5mjr@leeds.ac.uk> wrote in message
news:gfv9m2$968$1@fred.mathworks.com...
>i am trying to read in the 3rd value of the 1st numerical line 0.000 0.6149
>0.00834 ........ of the file below using textread. however i am having a
>lot of problems and it just will not read the line i want. it is the first
>time i have used this type of text scanning read in method and it is
>starting to annoy me. i want to read the value in exactly as is shown in
>the file below then assign it to the variable Cd.
>
>
> XFOIL Version 6.94
>
> Calculated polar for: test airfoil
>
> 1 1 Reynolds number fixed Mach number fixed
>
> xtrf = 0.500 (top) 0.500 (bottom)
> Mach = 0.100 Re = 1.000 e 6 Ncrit = 9.000
>
> alpha CL CD CDp CM Top_Xtr Bot_Xtr
> ------- -------- --------- --------- -------- ------- -------
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
>
>
>
> any help on this matter who be greatly appreciated as it does not seem to
> matter how i construct my code i just cannot get it to work :(
>
>

Re: problems using textread

Luca Zanotti Fragonara — Tue, 18 Nov 2008 20:57:02 -0500

fin=fopen('filename','rt')
A=textread(fin,'%f %f %f %f %f %f %f','endofline','\n','Headerlines',number);
fclose(fin);
where number is the number of the row where you want to start to read the file.
in A{3} you have your Cd, so
CD=A{3}(:,1);

"Matthew " <men5mjr@leeds.ac.uk> wrote in message <gfv9m2$968$1@fred.mathworks.com>...
> i am trying to read in the 3rd value of the 1st numerical line 0.000 0.6149 0.00834 ........ of the file below using textread. however i am having a lot of problems and it just will not read the line i want. it is the first time i have used this type of text scanning read in method and it is starting to annoy me. i want to read the value in exactly as is shown in the file below then assign it to the variable Cd.
>
>
> XFOIL Version 6.94
>
> Calculated polar for: test airfoil
>
> 1 1 Reynolds number fixed Mach number fixed
>
> xtrf = 0.500 (top) 0.500 (bottom)
> Mach = 0.100 Re = 1.000 e 6 Ncrit = 9.000
>
> alpha CL CD CDp CM Top_Xtr Bot_Xtr
> ------- -------- --------- --------- -------- ------- -------
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
> 0.000 0.6149 0.00834 0.00179 -0.1316 0.5000 0.1997
>
>
>
> any help on this matter who be greatly appreciated as it does not seem to matter how i construct my code i just cannot get it to work :(
>

Re: problems using textread

Luca Zanotti Fragonara — Tue, 18 Nov 2008 21:40:20 -0500

Sorry, I've posted 2 times, and this is the third. But I've posted a wrong code. I've written textread, while I was thinking at textscan. So the correct code is:
fin=fopen('filename','rt')
A=textscan(fin,'%f %f %f %f %f %f %f','endofline','\n','Headerlines',number);
fclose(fin);
CD=A{3}(:,1);

"Luca Zanotti Fragonara" <Luca_Zanotti@libero.it> wrote in message <gfva6u$grj$1@fred.mathworks.com>...
> fin=fopen('filename','rt')
> A=textread(fin,'%f %f %f %f %f %f %f','endofline','\n','Headerlines',number);
> fclose(fin);
> where number is the number of the row where you want to start to read the file.
> in A{3} you have your Cd, so
> CD=A{3}(:,1);
>

Re: problems using textread

Matthew — Wed, 19 Nov 2008 15:52:02 -0500

Luca,

thank you, it was a comn=bination of the headerlines and the %f's i was using i think??? but it is working fine now so thanks a lot!!

Matthew

"Luca Zanotti Fragonara" <Luca_Zanotti@libero.it> wrote in message <gfvco4$ke0$1@fred.mathworks.com>...
> Sorry, I've posted 2 times, and this is the third. But I've posted a wrong code. I've written textread, while I was thinking at textscan. So the correct code is:
> fin=fopen('filename','rt')
> A=textscan(fin,'%f %f %f %f %f %f %f','endofline','\n','Headerlines',number);
> fclose(fin);
> CD=A{3}(:,1);
>
> "Luca Zanotti Fragonara" <Luca_Zanotti@libero.it> wrote in message <gfva6u$grj$1@fred.mathworks.com>...
> > fin=fopen('filename','rt')
> > A=textread(fin,'%f %f %f %f %f %f %f','endofline','\n','Headerlines',number);
> > fclose(fin);
> > where number is the number of the row where you want to start to read the file.
> > in A{3} you have your Cd, so
> > CD=A{3}(:,1);
> >
>