Comments on: How our developers make MATLAB faster

By: Paul-Armand Verhaegen

Paul-Armand Verhaegen — Mon, 28 Jun 2010 15:06:30 +0000

Confirmed by testing:
Strmatch is confirmed to be at least several times slower than the strcmp family of function on R2008a.

Thank you for the indications and for the proposing coding.

By: Brad Phelan

Brad Phelan — Mon, 08 Sep 2008 07:09:46 +0000

Funny that this problem with rmfield has only just been noticed. I wrote a trivial mex file to solve this problem for my requirements about 3 years ago.

http://pastie.org/267994

It might not cover all bases but i remember it sped up my particular app significantly.

By: Duane Hanselman

Duane Hanselman — Fri, 05 Sep 2008 18:12:30 +0000

FYI…

% strmatch replacements
% strmatch is obsolete, strncmp and strcmp are built in
% case insensitive works too with strncmpi and strcmpi

idx=strmatch(str,strarray); % is replaced by
idx=find(strncmp(str,cellstr(strcell),length(str)));

% note that find( ) can be removed for logical results
% in any of these cases.

idx=strmatch(str,strcell); % is replaced by
idx=find(strncmp(str,strcell,length(str)));

idx=strmatch(str,strarray,’exact’); % is replaced by
idx=find(strcmp(strx,cellstr(strarray)));

idx=strmatch(str,strcell,’exact’); % is replaced by
idx=find(strcmp(strx,strcell));

By: Doug

Doug — Thu, 04 Sep 2008 14:23:31 +0000

Duane,

I just looked, I did not see an m-lint warning against STRMATCH in 2008a. However, I seem to recall what you mention also.

I have entered this into our internal enhancement tracking database.

Thanks,
Doug

By: Duane Hanselman

Duane Hanselman — Thu, 04 Sep 2008 00:20:40 +0000

Did anyone ever try replacing strmatch with strcmp (or its siblings as needed)? I recall mlint telling me that this is much faster since strcmp now works when one argument is a cell array of strings. If I am not mistaken, strmatch is really an obsolete function now.

TF = strcmp(‘str’, C) compares string str to the each element of cell array C, where str is a character vector (or a 1-by-1 cell array) and C is a cell array of strings.