MATLAB: How to populate a cell with a loop

.datloop

This is what I have with my code so far.
a = dir;
i=3;
d = a(i).name;
A = zeros(40,55);
while i<=43
  A = textscan(fopen(d),'%f %f %f %f %f %f %f %f %f %f %f %f %f %f %s %s %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %s %s %f %f %f %f %f %f %f %f', 'Delimiter',',','Headerlines',1);
  A_time = A{1,1};
  B_time = num2str(A_time);
  x = datenum(B_time,'yyyymmddHHMM');
  i=i+1;
end
I have 43 data files in my folder. when I run this, A becomes a 1×55 cell with data from the first file. I'd like to make it so that the A on the outside of the loop is populated with the cell data from each file folder. Please help

Best Answer

fmt=[repmat('%f',1,14) repmat('%s',1,2) repmat('%f',1,29) repmat('%s',1,2) repmat('%f',1,8)];   % legible (sorta') format string
d=dir('AppropriateString*.ext');                                  % setup dir() to return the wanted actual files
for i=1:length(d)                                                 % iterate over files found

  fid=fopen(d(i).name),'r');
  A(i)=textscan(fid,fmt,'Delimiter',',','Headerlines',1);
  fid=fclose(fid);
end
Will leave with cell array of one row per file.
Which specific columns are date/time data? The two sets of '%s' I presume?
datenum has been deprecated; better to use datetime instead and easier than textscan would be to use readtable.
Let us know the actual date format/location in the files and we can write specific conversion for it, too...
ADDENDUM
OK, if the string fields are really just 'nan' or variant thereof, use numeric format for them and convert them on input as well.
...
fmt=['%{yyyyMMddHHmmss}D' repmat('%f',1,54)]; % legible format string
for i=1:length(d)                             % iterate over files found
  fid=fopen(d(i).name),'r');
  A{i}=textscan(fid,fmt,'Delimiter',',','Headerlines',1,'collectoutput',1);
    fid=fclose(fid);
  end
using datetime class rather than the deprecated datenum for the date field.
You might also consider readtable depending on what your next step(s) are with these data.
Related Question