fill a vector inside a cycle

I have a script where I have to fill a vector like this example:

heads = (1:10);
vector_to_fill = zeros(1,5);

for i = 1 : heads
  if condition
    vector_to_fill(what index) = heads(i);
  end
end

my problem is that I don't know what index putting to that vector_to_fill.how can I slide that vector correctly? If i put the same index as i I leave zeros between element.

[Azzi Abdelmalek]

what do you mean?

[Salvatore Mazzarino]

Azz you what index should put to vector_to_fill?

Answer 1

[Azzi Abdelmalek]

clear
heads = 1:10;
k=0
for ii = heads
if rand(1,1)>0.5
  k=k+1
  vector_to_fill(k) = heads(ii)
end
end