On Sunday 30 November 2003 08:31, Oren Tirosh wrote:
On Fri, Nov 28, 2003 at 06:24:30PM -0500, Raymond Hettinger wrote: ...
students.sort(key=extract('grade')) # key=lambda r:r.grade students.sort(key=extract(2)) # key=lambda r:[2]
Why should the extract function interpret a string argument as getattr and an int argument as getitem?
I find the explicit version more readable:
students.sort(key=attrgetter('grade')) # key=lambda r:r.grade students.sort(key=itemgetter(2)) # key=lambda r:[2] students.sort(key=itemgetter('grade')) # key=lambda r:r['grade']
I concur: "overloading" extract to mean (the equivalent of) either getattr or getitem depending on the argument type doesn't look good, besides making it unusable to extract some items from dicts. Since these functions or types are going to be in operator, I think we can afford to "spend" two names to distinguish functionality (even though attgetter and itemgetter look nowhere as neat as extract -- I don't have better suggestions offhand). Alex