How to read string/numeric line from file, and parse out one number?

I can grab a specific line from a file, and store it. But however it's stored, I don't know how to pull out the 6th "value", and then use it as a number. Here's the file line:

259  FxR1                              757.6469       17.6892      704.9626      820.0703      115.1077    kN

Here's how I pull and store:

    fid2=fopen('file.txt');
     C=textscan(fid2, '%s', 1, 'delimiter', '\n', 'headerlines', 463-1); %get one specific line
     disp(C)
    fclose(fid2);

Want to get the 820.0703 value out, and use that.

Thanks in advance.

Answer 1

[dpb]

Many ways, one would be

...
fmt=['%*f %*s' repmat('%*f',1,3) '%f'];    % skip number/string/3numbers, read value
v=cell2mat(textscan(fid2,fmt,1,'headerlines', 463-1));
...

Alternatively, use the same format on the string read instead of the file.

[David Pesetsky]

Hmm, that method gives an error:

      v = cell2mat(textscan(fid2,fmt,1,'headerlines', 463-1));
        |
Error: The expression to the left of the
equals sign is not a valid target for an
assignment.

Matlab 2014b.

[dpb]

Did you catch/fix the typo of a missing closing quote in the fmt string assignment after the %*s before repmat? Would think it wouldn't get as far as the assignment, but mayhaps it's confused the parser differently in a later release or from a script file rather than command line...

With l containing your line, and the corrected format string

>> fmt=['%*f %*s' repmat('%*f',1,3) '%f'];
>> v=cell2mat(textscan(l,fmt,1))
v =
820.0703
>>

Or, do you have v already defined as something else could be a possibility, I suppose...if the above doesn't fix it, what does

which v

return?

[David Pesetsky]

It was the closing quote.