Index exceeds number of array elements

Hello,

Please excuse my naivety as a beginner with MATLAB but I am receiving an error message I'm struggling to get past. I am ultimately trying to plot a dataset.

for i=1:nVal
  [fline,count] = fscanf (fid,'%f %f %f %f %f',5);
  if (mod(i,20) == 1)
      fprintf ('%6.1f %7.2f\n', fline(1), fline(2) );	% display the time and x value as a check
  end
  t(i)  = fline(1);		% load vector of time values
  xm(i) = fline(2);		% load vector of x readings
  ym(i) = fline(3);		% load vector of y readings
  z1m(i) = fline(4);		% load vector of z1 readings
  z2m(i) = fline(5);		% load vector of z2 readings
end

Unrecognized function or variable 'nVal'.

The error message that is coming up is:

Index exceeds the number of array elements. Index must not exceed 0.

Error in untitled (line 40)

fprintf ('%6.1f %7.2f\n', fline(1), fline(2) ); % display the time and x value as a check

There is of course more code before and after this and as a noobie, I wasn't sure how much would have been required to help solve this solution but this is the section that appears to be causing the error. Any help is much appreciated!

Answer 1

[Torsten]

Insert

class(fline)
size(fline)

after

for i=1:nVal
    [fline,count] = fscanf (fid,'%f %f %f %f %f',5);

and see what type and size the variable "fline" has that you try to output in the following command

if (mod(i,20) == 1)
    fprintf ('%6.1f %7.2f\n', fline(1), fline(2) );	% display the time and x value as a check
end

[Tinman]

ans =

    'double'


ans =

     0     0

and still with the error message:

Index exceeds the number of array elements. Index must not exceed 0.

[Walter Roberson]

The fscanf was not successful in reading any numeric data from the line.

I suggest that at that point, you

linein = fgetl(fid);
[fline,count] = sscanf(linein,'%f %f %f %f %f');
if count < 5
    fprintf('Input error at i = %d, text of line is:\n%s\n', i, linein);
end

and examine what the actual input is.

[Tinman]

This is what I get back:

Input error at i = 0, text of line is:

and then the same error message as before for the same line of code

I'm a little lost here as to what this is all trying to tell me.

[Walter Roberson]

Is that within the

for i=1:nVal

loop? Because if it is, then i cannot be 0 there.

What the output is showing you is that your input is empty on that particular line.

Furthermore, fscanf() with a numeric % format will skip all leading white space.

• you might have reached end of file
• there might be several blank lines, followed by something that is not blank but starts with something that is not numeric.
• You might have accidentally opened the file with 'w' or 'w+' or 'a' permission instead of 'r' or 'r+' or 'a+' permission. 'w' and 'w+' would start by erasing everything in the file. 'a' (but not 'a+') would automatically position at the end of file so there might not be anything in position to read.
• Are you looping over files? Because if so then you might have forgotten to close a previous file and open a new one

[Tinman]

I've solved it Walter, thanks! So it appears that the actual document I was trying to read had the error which MATLAB was unable to deal with as coded which is exactly what you said. I also changed the opening of the file to 'r' which may have also helped too but with a small edit to the file trying to be read, it appears to have worked. Thank you.