graph theory if time equals 40189 graph all 40189's source and target

hello everyone , im wrote this code for if time(i) cell 40189 then create all array and group all 40189 information.after then digraph only this time data. But i have 40189 - 42380 about 24356 length data . how can create loop .2 weeks i cannot find a solution.

 data = xlsread('veri.csv');
  source = data(:,1)
  target = data(:,2)
  rating = data(:,3)
  time   = data(:,5)
  i = length(source)

for index = 1 :i

      if (time(index)== 40189 )
          s(index) = source(index)
          t(index) = target(index)
          weights(index) = rating(index);

      end;

      end;
      s( :, ~any(s,1) ) = []
      t( :, ~any(t,1) ) = []
      weights( :, ~any(weights,1) ) = []

      if ( max(s) > max(t))
          a = max(s)
      else
          a = max(t)
      end;

      G = digraph(s,t,weights,a)