MATLAB Central Newsreader - Issues Writing to File

Issues Writing to File

Ashley — Sat, 07 Nov 2009 13:28:01 -0500

I'm having trouble writing to a file using fprintf. The issues is I need to write lines like:

fprintf(' name='C:/Documents and Settings/ecslogon/Desktop/ME726_Project/Marco Test/Test_Job-3.odb'\n');

This means that I need to print " ' " to the file without ending the fprintf statement. How is this done?

The second issue is I need to write " ( " and " ) " to the file without ending the fprintf (see example below) or causing Matlab to give me an inblance error. How is this done?

fprintf(' INVARIANT, 'Max. Principal'), )), ))\n\n');

Thank you for your time,
Ashley

Re: Issues Writing to File

dpb — Sat, 07 Nov 2009 13:58:45 -0500

Ashley wrote:
> I'm having trouble writing to a file using fprintf. The issues is I
> need to write lines like:
> fprintf(' name='C:/Documents and ...

...

>> sprintf('%s','It''s an embedded ''.')
ans =
It's an embedded '.
>>

Double up on the apostrophes is one way; another is to insert the
numeric values w/ strrep in an existing string at a desired location or
use strcat or , to build the string.

>> pstrphe = double('''')
pstrphe =
39
>> char(pstrphe)
ans =
'
>> s = ['That', char(pstrphe), 's a string.']
s =
That's a string.
>>

for example. repmat() sometimes comes in handy for repeated strings as
well.

help strfun

to see the full ML repertoire from which to choose...

BTW, I assume you did get the max stress data read correctly?

--

Re: Issues Writing to File

Ashley — Sat, 07 Nov 2009 14:08:01 -0500

dpb <none@non.net> wrote in message <hd3uer$cnn$1@news.eternal-september.org>...
> Ashley wrote:
> > I'm having trouble writing to a file using fprintf. The issues is I
> > need to write lines like:
> > fprintf(' name='C:/Documents and ...
>
> ...
>
> >> sprintf('%s','It''s an embedded ''.')
> ans =
> It's an embedded '.
> >>
>
> Double up on the apostrophes is one way; another is to insert the
> numeric values w/ strrep in an existing string at a desired location or
> use strcat or , to build the string.
>
> >> pstrphe = double('''')
> pstrphe =
> 39
> >> char(pstrphe)
> ans =
> '
> >> s = ['That', char(pstrphe), 's a string.']
> s =
> That's a string.
> >>
>
> for example. repmat() sometimes comes in handy for repeated strings as
> well.
>
> help strfun
>
> to see the full ML repertoire from which to choose...
>
> BTW, I assume you did get the max stress data read correctly?
>
> --

Yes thank you I did get the max stress read correctly although I used a different method. Although what you suggested worked I was worried that it would fail if the max stress was for some reason written on a different line. A friend helped me write the following:

fid=fopen(filename,'r');
eofstat=0;

while (eofstat == 0);

   tline = fgetl(fid);
   [a,b] = size(tline);

    if b >= 9 & tline(1:9) == ' Maximum';
        find = 1;
        values = sscanf(tline, '%s %f' );
        max = values(8);

       break
    end
    eofstat = feof(fid);
end

fclose(fid);

Which works very well and doesn't care which line the max stress is writtne on. Thanks again for all your help.
Ashley

Re: Issues Writing to File

dpb — Sat, 07 Nov 2009 14:24:21 -0500

Ashley wrote:
...
> Yes thank you I did get the max stress read correctly although I used
> a different method. Although what you suggested worked I was
> worried that it would fail if the max stress was for some reason
> written on a different line. ...

No, that was the whole point of the 'Maximum' in the format string in
textread()--that _requires_ that the string be matched followed by the
value so that your certain that it isn't a differing one that will be read.

Otherwise, if there were a malformed file using '%s %f' would possibly
allow you to transparently get a value that wasn't the maximum w/o
knowing about it.

But, it's your data, suit yourself...

--

Re: Issues Writing to File

dpb — Sat, 07 Nov 2009 15:09:53 -0500

dpb wrote:
> Ashley wrote:
> ...
>> Yes thank you I did get the max stress read correctly although I used
>> a different method. Although what you suggested worked I was
>> worried that it would fail if the max stress was for some reason
>> written on a different line. ...
>
> No, that was the whole point of the 'Maximum' in the format string in
> textread()--that _requires_ that the string be matched followed by the
> value so that your certain that it isn't a differing one that will be read.
>
> Otherwise, if there were a malformed file using '%s %f' would possibly
> allow you to transparently get a value that wasn't the maximum w/o
> knowing about it.
>
> But, it's your data, suit yourself...

OH...dawned on me what your concern was -- it, indeed, somebody were to
change the format of number of lines/file ahead of the value not a fubar
in the file itself--yes, the textread() solution does require the format
be consistent whereas as long as they don't introduce a maximum
something else before of your intended one the posted solution will
handle it.

--