[Python-Dev] Re: PEP 279 (original) (raw)

Raymond Hettinger python@rcn.com
Tue, 2 Apr 2002 00:28:45 -0500

From: "Tim Peters" <tim.one@comcast.net>

> So now I'd like to choose between enumerate() and indexer(). Any > closing arguments?

I'm leaving that quote anonymous so nobody gives it more or less weight than it deserves . I prefer enumerate(), because a transitive verb is more appropriate than a noun. OTOH, enumerate() is just a fancy pants way of saying "countoff()", which is nicely confusable with operator.countOf if you're tired .

I agree. Enumerate is a direct, unequivocable verb that speaks directly to the idea of sequentially assigning numbers to things.

Countoff is cool, but is a little colloquial. Also, any of the words incorporating count (including itercount and countoff) have a subtle implicit suggestion of counting from one rather than zero -- "firstly, let's take item zero ..."

While indices have a clear meaning in Python, the old Dbase and SQL part of me is a little bugged by index(), indexed(), indexer() since sequential files are not at all like indexed files. When I index a database, sorting takes place. When I index a collection, sequencing is applied. Much different.

As a part of speech, indexer() doesn't work as well in a sentence: for linenum, line in indexer(file): ... # yuck!

Summary, I think we're down to subtle differences and have the following preference order:

  1. enumerate
  2. countoff
  3. indexed
  4. itercount

OTOH, no one has ever accused me of having good taste

Raymond Hettinger