[Python-Dev] Confusing listreverseiterator Behavior

[Jeff Hall]

I realized after I fired off my response that this was still bugging me...
it appears that the documentation is incorrect

from 2.1 Built-in Functions (v2.5 in case it matters... a quick search of
bugs doesn't seem to show anything though)
  *reversed*( seq) Return a reverse iterator. seq must be an object which
supports the sequence protocol (the __len__() method and the
__getitem__()method with integer arguments starting at
0). New in version 2.4. the above appears to only be true for lists. For
tuples and strings it creates a reverse OBJECT which behaves slightly
differently (notably by not including a len() method as you noticed)

I can't find how to actually create a "tuplereverseiterator" or
"stringreverseiterator" objects... nor does there appear to be a way to
create a "reversed" object from a list...

Just tested this
s = 'bob'
t = (1,2,3,4)
l = [1,2,3,4)
rs = reversed(s)
rt = reversed(t)
rl = reversed(l)

type(rs)
<type 'reversed'>
type(rt)
<type 'reversed'>
type(rl)
<type 'listreverseiterator'>
type(rs) == type(rt)
True
type(rs) == type(rl)
False

Surely this isn't intentional?

--------
Haikus are easy
Most make very little sense
Refrigerator
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-dev/attachments/20080826/2f616072/attachment.htm>