On 2007-01-04, Peter Otten <[EMAIL PROTECTED]> wrote: > 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
Thanks for the correction! That's very useful information. -- Neil Cerutti -- http://mail.python.org/mailman/listinfo/python-list
