Michael Hoffman schrieb: > The peephole optimizer now takes things like > > if 0: > do_stuff() > > and optimizes them away, and optimizes away the conditional in "if 1:". > > What if I had a function like this? > > def func(debug=False): > for index in xrange(1000000): > if debug: > print index > do_stuff(index) > > Could the "if debug" be optimized away on function invocation if debug > is immutable and never reassigned in the function? When performance > really matters in some inner loop, I usually move the conditional > outside like this: > > def func(debug=False): > if debug: > for index in xrange(1000000): > print index > do_stuff(index) > else: > for index in xrange(1000000): > do_stuff(index) > > It would be nice if this sort of thing could be done automatically, > either by the interpreter or a function decorator.
Just use the builtin __debug__ variable for that purpose. __debug__ is 'True' if Python is run normally, and 'False' if run with the '-O' or '-OO' command line flag. The optimizer works in the way you describe above (which it will not if you use a custom variable). Thomas -- http://mail.python.org/mailman/listinfo/python-list
