stripfile

 function [f,file] = stripfile(x,flag,sep)

 <x> is a string referring to a file (it is okay if the file
   does not actually exist).  if <x> ends in /, we automatically
   act as if that / does not exist.
 <flag> (optional) is whether to swap the output arguments.  default: 0.
 <sep> (optional) is the actual "/" character to use.  default is 
   the output of filesep.m.

 if <flag> is 0,
   return <f> as the string but with the file name removed.
   return <file> with the file name.
 if <flag> is 1, these arguments are swapped.

 history:
 2014/07/14 - make more general by defaulting <sep> to filesep.m.

 example:
 isequal(stripfile('blah/temp.png',[],'/'),'blah/')
 isequal(stripfile('temp.png',[],'/'),'')
 isequal(stripfile('ok/blah/',1,'/'),'blah')

0001 function [f,file] = stripfile(x,flag,sep)
0002 
0003 % function [f,file] = stripfile(x,flag,sep)
0004 %
0005 % <x> is a string referring to a file (it is okay if the file
0006 %   does not actually exist).  if <x> ends in /, we automatically
0007 %   act as if that / does not exist.
0008 % <flag> (optional) is whether to swap the output arguments.  default: 0.
0009 % <sep> (optional) is the actual "/" character to use.  default is
0010 %   the output of filesep.m.
0011 %
0012 % if <flag> is 0,
0013 %   return <f> as the string but with the file name removed.
0014 %   return <file> with the file name.
0015 % if <flag> is 1, these arguments are swapped.
0016 %
0017 % history:
0018 % 2014/07/14 - make more general by defaulting <sep> to filesep.m.
0019 %
0020 % example:
0021 % isequal(stripfile('blah/temp.png',[],'/'),'blah/')
0022 % isequal(stripfile('temp.png',[],'/'),'')
0023 % isequal(stripfile('ok/blah/',1,'/'),'blah')
0024 
0025 % input
0026 if ~exist('flag','var') || isempty(flag)
0027   flag = 0;
0028 end
0029 if ~exist('sep','var') || isempty(sep)
0030   sep = filesep;
0031 end
0032 
0033 % find any /
0034 locs = strfind(x,sep);
0035 
0036 % if none, return ''
0037 if isempty(locs)
0038   f = '';
0039   file = x;
0040 % otherwise, return entire string up to the last /
0041 else
0042   if locs(end)==length(x)  % ignore trailing /
0043     x = x(1:end-1);
0044     locs = locs(1:end-1);
0045   end
0046   if isempty(locs)
0047     f = '';
0048     file = x;
0049   else
0050     f = x(1:locs(end));
0051     file = x(locs(end)+1:end);
0052   end
0053 end
0054 
0055 % swap the output?
0056 if flag
0057   [f,file] = swap(f,file);
0058 end