fopen problem How does it work?

I have a file VarName3.txt like this:

[2.281000003
2.593500003
2.749750003
3.062250003
3.062250003...

and negative values too. It is 1x1000.

The code I am using is:

fid=fopen('VarName3.txt','r');
atensao=fread(fid,'float');
fclose(fid);

When I type in Comand Window to check atensao, the answer is:

 1.0e-03 *

    0.0425
    0.0000
    0.0000
    0.0006
    0.0000...

Why it doesn't work? What am I doing wrong? Could someone teach me? Thanks a lot.

Answer 1

[dpb]

fid=fopen('VarName3.txt','r'); 
atensao=fread(fid,'float'); 
fclose(fid);

Surprising got anything that reasonable. If the input file is actually an ASCII text file, then use fscanf instead of fread. fread is for stream unformatted data, not formatted.

fid=fopen('VarName3.txt','r'); 
atensao=fscanf(fid,'%f'); 
fclose(fid);

Or use one of the higher-level routines--while deprecated by TMW, textread is awfully handy for such simple cases as it wraps the fopen/fclose in the call and returns an array rather than a cell for the much fancier textscan

atensao=textread('VarName3.txt');

even allowing to dispense with the format string for simple numeric data such as your case. See

doc textread
doc textscan
doc fscanf

for more details

[André Luiz Regis Monteiro]

Thank you "dpb". I really appreciated. But when I check "atensao" it shows me number like: 2.2810 instead of 2.281000003 (from original file VarName3.txt). Do you know how can I fix it? Thank you again.

[Image Analyst]

Shows you how? Did you see the FAQ: http://matlab.wikia.com/wiki/FAQ#Does_MATLAB_only_calculate_to_4_significant_digits.3F

Answer 2

[Walter Roberson]

If you are reading text you should not be using fread() which is for reading binary files.

Have a look at fscanf(). Also have a look at textscan()

[André Luiz Regis Monteiro]

Thank you Walter Roberson. I used first option.