how to use nan matrix

Hi all,

please I want to Know why the P variable does not included in the p nan matrix like other variable this is the code:

 t=ones(30,41)*nan;
sal=ones(30,41)*nan;
Z=ones(30,41)*nan;
p=ones(30,41)*nan;

 for i=1:41
 ncload(['wod_00',num2str(cast(i)),'O.nc']);
 % pause
[n,m]=size(Temperature);

 if    (~exist('Pressure'))
    t(1:n,i)=Temperature(:);
    Z(1:n,i)=z(:);

 else
   t(1:n,i)=Temperature(:);
   Z(1:n,i)=z(:);
   sal(1:n,i)=Salinity(:);

   if lat>20
        exist('Salinity', 'var')
           sal(1:n,i)=Salinity(:);

         exist('Pressure','var');
           p(1:n,i)=Pressure(:);
    end
end

 end

THANK YOU FOR WHOM WHO HELP me :(

[per isakson]

t=ones(30,41)*nan; may be replaced by t=nan(30,41);

[Jan]

I do not see a variable called "P".

nan(30,41) is nicer than ones(30,41)*nan.

The exist('Salinity', 'var') line does not have any effects.

[lina]

per isakson and Jan simon Thank you VERY MUCH!

[dpb]

The above loop could be streamlined as...

 for i=1:41
   ncload(['wod_00',num2str(cast(i)),'O.nc']);
   [n,m]=size(Temperature);
   t(1:n,i)=Temperature(:);
   Z(1:n,i)=z(:);
   if exist('Pressure')
     sal(1:n,i)=Salinity(:);
     if lat>20
       sal(1:n,i)=Salinity(:);
       p(1:n,i)=Pressure(:);
    end
  end
end

since the t and z variables are stored either way, don't need the else clause at all...

[Jan]

@lina: You are welcome. Could you clarify what this means:

 the P variable does not included in the p nan matrix

[lina]

mr. simon I just solve the problem after ur correction above. thank you

dpd the loop is work