How to extract only certain values from a field in a structure array?

Hello, I am trying to output only certain values from a field in a structure array called Cells. The values I want are in the pos field, and I only want the value when the values in the Type field are equal to 1, and thus when P is 1. This is my code so far. It works in the command window and gives me all the variables, when I do not assign Cells(P).pos to a variable. But my problem is that when I assign Cells(P).pos to a variable it only gives me one value, versus for all the values P is true. How do I get all the values and still assign them to a variable? I tried to preallocate prof as an empty matrix but that didn't work either. Thanks!

P=[Cells.Type]==1; 
Prof= Cells(P).pos;

Answer 1

[Ahmet Cecen]

I am not aware of a way to do this without a for loop. If you run:

 P=[Cells.Type]==1

without the semi colon, you will see every element in the array correctly outputs the type check, yet they are not being captured as an array. The following should work:

 for i = 1:length(Cells)
   if Cells(i).Type == 1 
      Prof(i) = Cells(i).pos;
   end
 end

[Rasha Bara]

Thanks! That gave me the values I need! However, is there a way I can output only the values in Prof that are not zeros? I tried writing this, but that gave me an array of logicals versus only the actual values of Prof that are not zero.

P= Prof~=0;

[Ahmet Cecen]

 ii = 0;
 for i = 1:length(Cells)
   if Cells(i).Type == 1 
      ii = ii + 1;
      Prof(ii) = Cells(i).pos;
   end
 end

OR following your idea, deleting the zero entries after the fact:

 for i = 1:length(Cells)
   if Cells(i).Type == 1 
      Prof(i) = Cells(i).pos;
   end
 end
 Prof (Prof==0) = [];

[Rasha Bara]

Thanks! That worked perfectly!

Answer 2

[Walter Roberson]

 P=[Cells.Type]==1; 
 Prof= vertcat(Cells(P).pos);

[Ahmet Cecen]

Ooh I like this one. Sneaky.