On Sun, Dec 30, 2012 at 4:10 PM, Ned Batchelder <ned@nedbatchelder.com> wrote:
I wonder at the underlying philosophy of things being accepted or rejected in this way.

I'm no expert on the subject but here are a few criteria for builtin method inclusion:

* Useful - show many popular use cases, e.g. attach many links to various lines on github/stackoverflow/bitbucket.
* Hard to get right, i.e. user implementations tend to have bugs.
* Would benefit greatly from C optimization
* Have a great, obvious, specific, readable name
* Don't overlap with anything else in the stdlib - TSBOAPOOOWTDI
* Consistent with the rest of python, e.g.
* Community approval
* BDFL approval

Brett wrote a bit on stdlib inclusion which may be relevant http://mail.python.org/pipermail/python-3000/2006-June/002442.html

"that way may not be obvious at first unless you're Dutch."

Yuval