Dynamic-variable sized arrays in matlab - matlab

Question

This code is working but needs to be improved for efficient calculations
anisLoc=[];% Variable sized array
PiezoLoc=[]; % Variable sized array
for i=1:q % Looking in all q
if ~isempty(LayerProp{i}.c)% if c is not empty then
anisLoc=[anisLoc,i];
c{i}=LayerProp{i}.c;
end
if ~isempty(LayerProp{i}.e) % if e is not empty then
% if LayerProp{i}.e(3,3)
PiezoLoc=[i;PiezoLoc];
e{i}=LayerProp{i}.e;
% end
end
end
anisLoc and Piezoloc are variable sized arrays. I set them on their maximum values q
but they change size and could not empty them after so they produce same answer from initial code!!
anisLoc=zeros(q,1);% Variable sized array
PiezoLoc=zeros(1,q);% Variable sized array
% This loop checks for specific input in data in all
for i=1:q % Looking in all q
if ~isempty(LayerProp{i}.c)% if c is not empty
anisLoc=[i;anisLoc];
c{i}=LayerProp{i}.c;
end
if ~isempty(LayerProp{i}.e) % if e is not empty
% if LayerProp{i}.e(3,3)
PiezoLoc=[PiezoLoc,i];
e{i}=LayerProp{i}.e;
% end
end
end

Answer 1

I believe this should be quite a bit faster:
anisLoc=zeros(q,1);% Variable sized array
PiezoLoc=zeros(1,q);% Variable sized array
% This loop checks for specific input in data in all
k = 0;
m = 0;
for ii=1:q % Looking in all q
if ~isempty(LayerProp{ii}.c)% if c is not empty
k = k + 1;
anisLoc(k)=ii;
c{ii}=LayerProp{ii}.c;
end
if ~isempty(LayerProp{ii}.e) % if e is not empty
% if LayerProp{ii}.e(3,3)
m = m + 1;
PiezoLoc(m) = ii;
e{ii}=LayerProp{ii}.e;
% end
end
anisLoc(k+1:end) = [];
PiezoLoc(m+1:end) = [];
end