referencing polynomial variables
Suppose I have a polynomial $f$ in the variables $x_1, \dots, x_5$ defined by something like
f = 0 for counter in range(1,5): f += mylist[counter] * var('x' + str(counter))
where mylist is some list of integers. Then I can evaluate $f$ by e.g.
Question: How do I do this evaluation when $f$ is in $n>>0$ variables?
I want to write something like
for counter in range(1,n): f = f.subs(var('x' + str(counter))=counter)
but this isn't a valid argument for subs. This must be some way to coerce this to work.