Need an Elegant Sorting Solution for Directory File Names

I have a directory of filenames, (within a files structure array) structured like this:

cdef2.20140101.pdef.txt

cdef2.20140102.pdef.txt

....

pdef.gdef.201300101-20130105.txt

pdef.gdef.201300106-20130110.txt

....

I need to reorder these (ascending order from oldest to newest) according to the dates embedded within these file names which are formatted like YYYYMMDD. I've explored several options, but I'm seeking an elegant solution without do loops. Any tips or suggestions would be appreciated.

[Sandeep Mishra]

Which date to consider in file names like pdef.gdef.201300101-20130105.txt ?

The file naming also doesn't contain any special pattern to avoid loop,

If you can change cdef2.20140101.pdef.txt to cdef2.pdef.20140101.txt, then it will be easier to split all files names using delimiter ('.')

[John Cruce]

Needing to sort by the first date in pdef.gdef.201300101-20130105.txt (i.e., 20130101). I considered running a shell script to rename the files but trying not to add another step.

[Sandeep Mishra]

Can we assume that there exist only two type of files?

One which starts with cdef2 and one which starts with pdef?

Answer 1

[Voss]

filenames = { ...
    'cdef2.20140101.pdef.txt'; ...
    'cdef2.20140102.pdef.txt'; ...
    'pdef.gdef.20130101-20130105.txt'; ...
    'pdef.gdef.20130106-20130110.txt'}

filenames = 4×1 cell array
    {'cdef2.20140101.pdef.txt'        }
    {'cdef2.20140102.pdef.txt'        }
    {'pdef.gdef.20130101-20130105.txt'}
    {'pdef.gdef.20130106-20130110.txt'}

dates = regexp(filenames,'\d{8}','match','once');
[~,idx] = sort(dates);
sorted_filenames = filenames(idx)

sorted_filenames = 4×1 cell array
    {'pdef.gdef.20130101-20130105.txt'}
    {'pdef.gdef.20130106-20130110.txt'}
    {'cdef2.20140101.pdef.txt'        }
    {'cdef2.20140102.pdef.txt'        }