I would to save the values for post processing from file output, can you help me?

I have a file .txt which i would to obtain the values for post processing. For this in Matlab i am using:

outputfile=fopen(postproces.dat,'r');

But the file have this line:

fan= 30.000 bes = 2.3700 doe = 15.490

and i would to catch 2.3700 and save it into a variabile bes in Matlab. Thanks.

Answer 1

[per isakson]

Try this

>> num = cssm('h:\m\cssm\postprocessing.txt')
num =
         3.15

where the file, cssm.m, contains the following code

function    num = cssm( ffs )
    str = fileread( ffs );
    xpr = '(?<=Cref\s*=\s*)[0-9.]+';
    cac = regexp( str, xpr, 'match', 'once' );
    num = str2double( cac );
end

2017-05-07: There is an issue with this regular expression, '(?<=Cref\s*=\s*)[0-9.]+'. It matches the value following any word that ends with the string, Cref, e.g. xyzCref. Thus, add the beginning of word anchor, \<, so that the expression reads '(?<=\<Cref\s*=\s*)[0-9.]+'.

Version 2.0

>> num = cssm('h:\m\cssm\postprocessing.txt',{'Sref','Cref','Bref'})
num =
           30         3.15        10.95       

where

function    num = cssm( ffs, names )    
    narginchk(1,2)
    if nargin == 1
        names = {'Cref'};
    else
        if isa( names, 'char' )
            names = {names};
        elseif not( iscellstr( names ) )
            error('The second input argument, "%s", has wrong type') 
        end
    end
    
    str = fileread( ffs );
    len = length( names );
    num = nan( size( names ) );
    for jj = 1 : len
        xpr = ['(?<=\<', names{jj}, '\s*=\s*)[0-9.]+'];
        cac = regexp( str, xpr, 'match', 'once' );
        num(jj) = str2double( cac );
    end
end

[mattvanviore]

I'm using num = cssm( ffs ) and have a problem when the value is negative, and it appears NaN.

[per isakson]

What's "value is negative" and what's "appears NaN" ?

Answer 2

[Image Analyst]

You can probably use csvread(), dlmread(), readtable(), importdata(), textscan(), or fgetl(). (Just one of those functions of course!)

If none of those work, attach 'postproces.dat' so we can figure it out for you.

[mattvanviore]

in this case i want to save into variable cref the value 3.1500 without copy and paste.

[Image Analyst]

OK.

But we are still waiting.

Any idea when you will attach your data file? Come on, make it EASY for people to help you, not hard.

I need to leave now but might check back later today, or tomorrow.

[mattvanviore]

I want to save automatically as a variable Cref the value 3.1500 and as variable Cdind the value 0.1076431. I am using this code for the scan:

    dati=fopen(['.\folder\postprocessing.txt'],'r');  
    for i=1:8
        tline=fgets(dati);
    end

[per isakson]

Your file, postprocessing.txt, looks like this

---------------------------------------------------------------
 Vortex Lattice Output -- Total Forces

 Configuration: ALA ANALISI lambda0.2-massa 2000kg-AR 4                     
     # Surfaces =   2
     # Strips   =  40
     # Vortices = 240

  Sref =  30.000       Cref =  3.1500       Bref =  10.950    
  Xref =  0.0000       Yref =  0.0000       Zref =  0.0000    

  CDvis =   0.00000     CDind = 0.1076431

Do the files always have 12 lines and this format?

What about the line, fan= 30.000 bes = 2.3700 doe = 15.490 , of your question?

Do you want to capture only the value of Cref ?