Neil Cerutti wrote: > Another trick is to factor the key application out of the sort. > This may be a good idea if when you want to minimize the number > of times your key function is called. > > The idea is to mangle the list temporarily so you can use an > unkeyed sort, and then unmangle the sorted data. Here's a silly > example using a phone directory that's not stored in a format > that's easy to sort.
No need to jump through these hoops; list.sort(key=keyfunc) calls keyfunc() exactly once per list item: >>> from random import shuffle >>> items = range(-5, 10) >>> shuffle(items) >>> count = 0 >>> def key(value): ... global count ... count += 1 ... return abs(value) ... >>> items.sort(key=key) >>> count 15 Peter -- http://mail.python.org/mailman/listinfo/python-list
