On Thu, Jun 19, 2014 at 3:48 AM, <subhabangal...@gmail.com> wrote: > I am trying to see this line, > prev_f_sum = sum(f_prev[k]*a[k][st] for k in states) > > a[k][st], and f_prev[k] I could take out and understood. > Now as it is doing sum() so it must be over a list, > I am trying to understand the number of entities in the list, thinking > whether to put len(), and see for which entities it is doing the sum.
It's summing a generator expression, not a list. If it helps to understand it, you could rewrite that line like this: values_to_be_summed = [] for k in states: values_to_be_summed.append(f_prev[k]*a[k][st]) prev_f_sum = sum(values_to_be_summed) So the number of entities in the list is len(states). -- https://mail.python.org/mailman/listinfo/python-list