How to vary the interval of this matrix?

Thank you all for the reply. I already solved, in part, the problem I had, but now I have another. I have this line of code:

prueba=['MK_G', num2str(px(j,1)),'(4:6,4:6)'];

where 'MK_G', num2str (px (j, 1)) are N number of matrices that are already created. but I require, in some way, that the intervals of the matrix that I am evaluating (in this case 4: 6,4: 6) are in some way variable. I thank you for your collaboration with this new problem.

[jonas]

What do you mean by variable? How do you want to set the interval?

[Pedro Guevara]

Thank you very much for your help.

with variable I mean that it is not unique (as in this case where the intervals are (4: 6,4: 6), but that they depend on a variable that is already established. An example mode (although I know it's wrong) would be something like this:

 i=1; 
 For i = 1:10 
  prueba=['MK_G', num2str(px(j,1)),'(i:i+2,i:i+2)'];
 end

[Star Strider]

‘I already solved, in part, the problem I had, ...’

Please link to it to provide a context.

[Pedro Guevara]

   while  i>=1 && i<=VarElem_F %while 2 start           
       [px, py]=find(Nodos==datos(i,col)) %Busca posicion de nodos iguales 
       if length(py)==1
        jj=1;
        j=0;
       else 
        jj=1;  
        j=1;
       end   
       if (py(jj,1)==1 && py(j+1,1)==1) % If start 1
         for j = 1: length(px)  
         prueba=['MK_G', num2str(px(j,1)),'(1:3,1:3)'];
         prueba=eval(prueba);
         aux=aux+prueba;
         M_cons=aux;
         end
         prueba=0;
         aux=0;
         j=1;
         px=0;
         py=0

       elseif py(j,1)==2 && py(j+1,1)==2
         for j = 1: length(px)  
         prueba=['MK_G', num2str(px(j,1)),'(4:6,4:6)'];
         prueba=eval(prueba);
         aux=aux+prueba;
         M_cons=aux;
         end
         prueba=0;
         aux=0;
         j=1;

       elseif py(jj,1)~=py(j+1,1)
         for j = 1: length(px)  
         prueba=['MK_G', num2str(px(j,1)),num2str(j+1:j+2,j+1:j+2)];
         prueba=eval(prueba);
         aux=aux+prueba;
         M_cons=aux;
         end

         prueba=0;
         aux=0;
         j=1;
       elseif py(jj,1)~=py(j+1,1)    

       end % If end 1
      if i == VarElem_F && col==6 %If start 2
       col=7;
       f = 1;
       i=1;
      else
       i=1+i;
      end %If end 2
    end %while 2 end

[Steven Lord]

Looks like a continuation of this Answer.

[jonas]

Ugh.. Looks like he didn't pick up on the advice regarding dynamic variables.

Answer 1

[jonas]

i is your variable, then

formatSpec = '(%d:%d,%d:%d)';
str = sprintf(formatSpec,i,i+2,i,i+2)
prueba=['MK_G', num2str(px(j,1)),str];

You want the length of the interval to be variable as well? Just change the 2 to a variable.

[Pedro Guevara]

I will try this code. thank you very much.

[jonas]

No problem! I changed to sprintf for building the string instead, a bit more elegant.

EDIT: Ugh... Don't name variables dynamically. It's not good practice. Better use cell arrays or dynamic field variables.