On Fri, 6 May 2016 12:57 pm, Stephen Hansen wrote: > On Thu, May 5, 2016, at 07:46 PM, Dan Sommers wrote: >> On Thu, 05 May 2016 18:37:11 -0700, Stephen Hansen wrote: >> >> > ''.join(x for x in string if x.isupper()) >> >> > The difference is, both filter and your list comprehension *build a >> > list* which is not needed, and wasteful. The above skips building a >> > list, instead returning a generator ... >> >> filter used to build a list, but now it doesn't (where "used to" means >> Python 2.7 and "now" means Python 3.5; I'm too lazy to track down the >> exact point(s) at which it changed): > > Oh, didn't know that. Then again the OP was converting the output of > filter *into* a list, which wasted a list either way.
In Python 2.7, run `from future_builtins import *` to get most of the Python 3 behaviour: py> filter(None, []) [] py> from future_builtins import * py> filter(None, []) <itertools.ifilter object at 0xb7ee3e8c> -- Steven -- https://mail.python.org/mailman/listinfo/python-list
