On Tuesday, 3 March 2015 16:09:31 UTC, Chris Angelico wrote: > On Wed, Mar 4, 2015 at 2:56 AM, Charles Heizer wrote: > >> Personally, I prefer to not use a lambda: > >> > >> def name_version(elem): > >> return elem['name'], LooseVersion(elem['version']) > >> > >> result = sorted(mylist, key=name_version, reverse=True) > > > > Peter, thank you. Me being new to Python why don't you prefer to use a > > lambda? > > Using lambda is fine if it's really clear what's going on (usually, if > it's an extremely simple function), but if your expression goes across > multiple lines because of the function parameter, it's usually simpler > to break the function out into a separate def statement and then use > that. There's ultimately no difference[1] between a lambda function > and a def function, apart from the fact that a function created with > lambda always has the name "<lambda>". > > ChrisA > > [1] Modulo bugs, eg a weird edge case with lambda and yield; certainly > no intentional difference.
The main point is that a def gives your function a name, whereas lambda is unnamed. It sometimes feels harder to have to think of a name for something that seems simple, like your key function. But when you come back to it in a few months, the name is incredibly useful documentation as to what's going on. Paul -- https://mail.python.org/mailman/listinfo/python-list
