output of evalc

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Jaap
Jaap 2012-1-9
Hi, I am trying to load the filenames of 10000+ files (on a network path).
dir & ls seem the obvious commands, but they are both slow (33s for 18k files).
evalc on the other hand takes less than a second. (evalc('dir(...)')) however, the output is in a 1-d char array consisting of all filenames. There are spaces in the filenames as well, so that makes seperating a bit troublesome.
is it possible to get a different output format, or does anyone know a different "solution"?
Thanks! Jaap
PS. It's on a 32bit winXP
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Jaap
Jaap 2012-1-10
that would certainly be a good approach. however, it's a company network drive, in which I would like to keep the traffic one-way.
Jaap
Jaap 2012-1-10
other people are going to use this as well, who possibly do not have write access.

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Daniel Shub
Daniel Shub 2012-1-10
It seems that
evalc(['dir(', FilePath. ')'])
should go faster than
D = dir(FilePath);
since the evalc method only gets the file names while the direct call gets additional information. On a local filesystem, it probably doesn't matter much, but over a network it could make a big difference.
What about using the system call. On Windows that would be
[~, filenameArray] = system('dir /b');
and on Linux it would be
[~, filenameArray] = system('ls -1');
(note it is a one and not an el). . If you have oddly named or hidden files you may need more parameters.
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Daniel Shub
Daniel Shub 2012-1-10
I wouldn't extrapolate between what MATLAB does to get the directory information over a network share and how system level calls do it. My guess is it is both OS and mount type dependent. Is this a samba/windows share mount?
Jaap
Jaap 2012-1-10
I'm not quite sure, but it seems to be a regular network drive (visible under my computer etc).

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Jan
Jan 2012-1-9
Are you sure that Str = evalc(['dir(', FilePath. ')']) and D = dir(FilePath); have such a large speed difference?! Or did you just call dir at first, such that evalc('dir') can access the cached data?
Please post a copy of the used code.
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Titus Edelhofer
Titus Edelhofer 2012-1-10
Hmm, when scanning the output of evalc you already pointed out the main obstacle: filenames with spaces will give you a hard time (probably making this approach unusable).
Jaap
Jaap 2012-1-10
Thank you titus, indeed the same experience I had. there is something possible with strfind and filename extentions to search for filenames in a large string, but then I think I would prefer the slower approach.

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Titus Edelhofer
Titus Edelhofer 2012-1-10
But you could try something similar:
p = s{2};
[a,b]=system(['dir /B "' p '"']);
It took about half the time of the dir() call ...
Titus

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