MATLAB: Struggling to store indexing variable as an array.

arraycell arrayindexindexingMATLABsprintfstring

I am trying to store a list of file names which have been retrieved from a folder.
Any help would be appreciated; here is what I have so far:
File = zeros(1,10);
for i=1:10    
    File(1,i) = sprintf('%s%05d%s', 'A', i, '.dat');
end
I get the error message: "Subscripted assignment dimension mismatch."
I would like the files to be stored as:
File = [A00001.dat A00002.dat ... A0000N.dat]
Hopefully it is clear what I'm trying to achieve.
If I use the code:
File = zeros(1,10);
for i=1:10    
    File = sprintf('%s%05d%s', 'A', i, '.dat');
end
It runs; however, it only stores the final File name (in this case, "A00010.dat") rather than a 1×10 array of the first 10 File names.
Thanks

Best Answer

Each character of a string is one element of an array. So File = zero(1, 10) will only let you store 10 characters, not 10 strings.
Because all your strings are the same length, you could store all of them in a 2D char array, with each row a string, and each column one of the 10 characters.
filenames = zeros(10, 10);  %space for 10 strings of 10 characters
for row = 1:10
   filenames(row, :) = sprintf('%s%05d%s', 'A', row, '.dat');
end
%to access a string:

s = filenames(stringindex, :)
However, much better would be to store your strings in a cell array, where each string is an element of the cell array. It's much safer, strings can be different sizes, the above will error if a string is not exactly 10 characters:
filenames = cell(1, 10); %space for 10 strings of arbitrary length
for sidx=1:10    
   filenames{sidx} = sprintf('%s%05d%s', 'A', sidx, '.dat');
end
%to access a string:
s = filenames{stringindex}
Finally, note there is an undocumented/unsupported function (use at your own peril) that can replace the creating and filling of the cell array: sprintfc:
filenames = sprintfc('A%05d.dat', 1:10)
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