How to end a loop with unknown length before it fails

I'm trying to build a for end loop which will be used for thousands of different files each with different length. I get an error (Index exceeds matrix dimensions.) when the length of the loop is longer then the file itself.

I've been trying to implement a while / if statement but haven't succeeded. Anyone could advise?

if true
files = dir([datdir 'MV2*']);   
  for j=1:length(files)
      fid = fopen([datdir files(j).name],'rt');
     for p=1:10
         tmp=fgetl(fid);
     end
     for i=1:500
         for j=1:3
             tmp=fgetl(fid);
         end
    ind=strfind(tmp,'LOCAL')
    date=tmp(14:21)
    time=tmp(23:28)
    t=[t;datenum(date,'yyyymmdd')+datenum(time,'HHMMSS')-734869];
         for j=1:3
             tmp=fgetl(fid);
         end
     C=textscan(fid,'%f %f');
     ssc=[ssc;mean(C{2})];
     end
         fclose(fid);    
  end
  % code
end

The error comes from the line with date=tmp(14:21). (so also time=tmp(23:28)

Probably i could manage myself if someone could tell me where i should implement the while statement.

Thanks a lot in advance! :)

[Adam]

It is hard to recommend something without understanding your files. Your code suggests you expect your files to have a format that includes the date and time at those specified locations. If that is the case then there is a problem with one of your files, if it isn't the case you need more clauses around your code that makes these expectations.

e.g.

if numel( tmp ) >= 21
   date = tmp(14:21);
end

[Yuri Engelshoven]

The problem is that the file wants to continue doing loops although there is no more data left in the file. All the files are formatted exactly the same only thing is that some are 100 lines and some up to 1500.

A file is included.

Answer 1

[Image Analyst]

Don't use date as the name of a variable - it's already the name of a built-in function.

Why not put a breakpoint at that line and see what tmp is? I bet it's not what you were expecting.

Also, next time put the complete error message (ALL the red text), not just a small part snipped out of it.

[Yuri Engelshoven]

Thanks for your answer. The entire error message is:

Index exceeds matrix dimensions.

Error in test (line 16) date=tmp(14:21);

The error only occurs as soon as a file is read in which the loop is to long for the data in the file. I know this since the last tmp value is the last date of the file. and altough date is already a function, i doesn't seem to bring any problems since it states the date correctly each time.

[Image Analyst]

Look at the help for fgetl(). You need to add something like this after each time you call fgetl():

if ~ischar(tmp)
  break;
end

[Yuri Engelshoven]

Thanks a lot! Just by adding that exact piece of coding the problem was solved!

[Image Analyst]

You're welcome. Can you then officially mark the Answer as "Accepted" and vote for it?