Comments on: A functional task, I am sure

By: Wolfram

Wolfram — Thu, 21 Feb 2008 08:47:03 +0000

thank you alex!
just for those like me, who didnt know DSU=”decorate-sort-undecorate”, as Bär mentioned …
and btw i just found http://www.strayneuron.com/blog/archives/298 solving the same problem, glad i am not alone

thx all

By: Alex Martelli

Alex Martelli — Wed, 20 Feb 2008 22:41:52 +0000

Actually, your 1-liner is returning key-value pairs (sorted by value), not just keys sorted by values (IDs sorted by rank, in your case); for the latter task, there’s an even simpler and more elegant 1-liner:

sorted(d, key=d.get)

The key= feature of sort/sorted internally does DSU at high speed and with maximal precision (it will never compare ANYTHING but the specified sorting key; items with identical sorting keys remain in the same order as they were in the input), so there’s little need nowadays to delve into implementing DSU by hand (and I say that happily, even though years ago my articles, posts and books were instrumental in popularizing DSU;-).

Alex

By: Bär

Bär — Tue, 19 Feb 2008 16:35:21 +0000

You use the decorate-sort-undecorate pattern.
http://wiki.python.org/moin/HowTo/Sorting.

By: Daniel Lange

Daniel Lange — Tue, 19 Feb 2008 16:18:40 +0000

Or this (Python 2.4+)?
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/304440

By: Daniel Lange

Daniel Lange — Tue, 19 Feb 2008 16:13:46 +0000

Does this help?
http://aspn.activestate.com/ASPN/Python/Cookbook/Recipe/52306