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From: Luna Moon on 4 Feb 2010 09:51
function result=mytryfunc(x, y, z)

if isundefined(y)
do something...
end;

if isundefined(z)
do something...
end;

But there is no such command called "isundefined" in Matlab...

So I want to write my own "isundefined" function to detect undefined
arguments...

How to do that?

Thanks a lot!
From: Jos (10584) on 4 Feb 2010 10:07
Luna Moon <lunamoonmoon(a)gmail.com> wrote in message <8f077866-ef54-4f60-b327-af754c70d39e(a)v5g2000vbb.googlegroups.com>...
> function result=mytryfunc(x, y, z)
>
> if isundefined(y)
> do something...
> end;
>
> if isundefined(z)
> do something...
> end;
>
> But there is no such command called "isundefined" in Matlab...
>
> So I want to write my own "isundefined" function to detect undefined
> arguments...
>
> How to do that?
>
> Thanks a lot!

How would you define "undefined" here? Is someone is calling your function like this
mytryfunc(1)
do you assume, as most functions do, that Y and Z are missing?
What about the call
mytryfunc([],2,3)

Take a look at NARGIN and ISEMPTY, and use a couple of IF's to set the 'undefined' variables to a default value.

if nargin<3 || isempty(Z),
Z = ..
end
if nargin < 2 || isempty(Y),
% note that Z has been set to default already
Y =
end

hth
Jos
From: Walter Roberson on 4 Feb 2010 10:43
Luna Moon wrote:
> function result=mytryfunc(x, y, z)
>
> if isundefined(y)
> do something...
> end;
>
> if isundefined(z)
> do something...
> end;
>
> But there is no such command called "isundefined" in Matlab...
>
> So I want to write my own "isundefined" function to detect undefined
> arguments...
>
> How to do that?

if ~exist('y','var')
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