listing folders in directory with specific strings

I have a directory full of folders. I want to only list (and count) those with a specific naming format that starts with a numerical string and not any other folders in that directory. How can I do this? for example: FolderA contains these subfolders

180705-France, 180705-Germany, refdata

I want to list and count only the folders under folder A that start with a numeric string. In this case, the list should return '180705-France' and '180705-Germany', and a length(dirlist) should return 2.

something like,

pathn =['D:\FolderA'];
list= dir([pathn '\1*']);
len =length(list);

would work, but I need it to work for any folder whose name begins with numbers 0-9.

I tried using regexp but couldn't figure out how to get it to work. If I figure it out, I'll post it here, but I'm sure someone already knows how to do this....thanks.

[Stephen23]

Note that these square brackets do nothing at all:

pathn =['D:\FolderA'];

Square brackets are a concatenation operator, and that code is not concatenating anything together (the char vector is already a char vector). All that is needed is:

pathn = 'D:\FolderA';

https://www.mathworks.com/matlabcentral/answers/35676-why-not-use-square-brackets

[Jorge Rivé]

yes, thanks --I know...I started writing the question one way and then simplified it to avoid confusion. The path was a concatenation of strings before I changed it....

Answer 1

[Paolo]

You can work around it with a dos command:

[status,cmdout] = dos("dir *")
list = regexp(cmdout,'\d{6}-[A-Za-z]+','match');
len =length(list);

or alternatively:

s = dir;
list =regexp({s.name},'\d{6}-[A-Za-z]+','match');
len = length(find(~cellfun(@isempty,list)));

[Jorge Rivé]

thank you, the dos command version worked, but the alternative provided does not. list returns an array of empty cells.... Your first solution does the trick for me -- Thanks.

Answer 2

[Fangjun Jiang]

dir() does not have the regexp option. I can think of this way

a=dir;
b=char({a([a.isdir]).name});
len=sum(isstrprop(b(:,1),'digit'))