Adding Data to a structure

I know this must be simple but I just can't find it. I have a loop which loads data from files. I produce a structure from the data in the file. How do I add more entries (not fields) to the structure on the next pass of the loop. What I am looking for is a single structure (collected_a) which has all of the data from multiple files. The example below doesn't work as you can't reference a structure as (end +1). What is the right way to do this?

for i = 1:10
    fid=fopen(file(i))
    FormatString=repmat('%s',1,78);                                                  
   chaninfo = textscan(fid,FormatString,'CollectOutput',1);
   fclose(fid);
   columnHeadings =    {'Reading' 'Station' 'Line' 'RL' 'Lat' 'Long' 'Loop' 'Chan' 'Axis' 'NumChans' 'Time'};
  a = cell2struct(dat(:,2:12),columnHeadings,2);
 collected_a(end +1) = a;
end

Answer 1

[Walter Roberson]

(end+1) is fine for adding a single entry:

>> foo = struct('cliche', {'bird in hand'}, 'accuracy', {1/2})
foo = 
      cliche: 'bird in hand'
    accuracy: 0.5
>> foo(end+1) = struct('cliche', {'stitch in time'}, 'accuracy', {1/9})
foo = 
1x2 struct array with fields:
    cliche
    accuracy

If you are adding multiple entries, then use (end+1 : end+length(a))

[Glenn]

Thanks. I made that work.

Answer 2

[Oleg Komarov]

A reduced example, try to port it to your case:

columnHeadings = {'Reading' 'Station'};
% Preallocate structure
a(1:10)        = cell2struct(repmat({[]},numel(columnHeadings),1),columnHeadings,1);
% I am assuming the data has always the same number of fields (cells)
dat            = {rand(10),rand(20)};
for i = 1:10
    a(i) = cell2struct(dat',columnHeadings,1);
end

[Glenn]

Thanks for the quick response. Unfortunately, can't preallocate as I don't know how many entries are in each file.

[Oleg Komarov]

Preallocation is not mandatory.