[ python-Bugs-1003935 ] xrange overflows

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Bugs item #1003935, was opened at 2004-08-05 15:16
Message generated for change (Comment added) made by loewis
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>Category: Documentation
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Hallvard B Furuseth (hfuru)
Assigned to: Nobody/Anonymous (nobody)
Summary: xrange overflows

Initial Comment:
These restrictions are undocumented both in the
xrange doc string and in the reference manual
(Info node 'XRange Type'):

  >>> xrange(maxint, maxint + 10)
  Traceback (most recent call last):
    File "<stdin>", line 1, in ?
  OverflowError: long int too large to convert to int

  >>> xrange(-100, maxint)
  Traceback (most recent call last):
    File "<stdin>", line 1, in ?
  OverflowError: xrange() result has too many items

I hope the overflows below are bugs and not
features.  It works if 3/-3 is replaced with 1/-1:

  >>> xrange(0, maxint, 3)
  Traceback (most recent call last):
    File "<stdin>", line 1, in ?
  OverflowError: integer addition

  >>> xrange(0, -maxint, -3)
  Traceback (most recent call last):
    File "<stdin>", line 1, in ?
  OverflowError: integer addition

Python installation:

  Python 2.3.3 (#1, May 25 2004, 20:22:36) 
  [GCC 3.2.3] on sunos5
  Type "help", "copyright", "credits" or "license"
for    more information.
  >>> from sys import maxint
  >>> "%x" % maxint
  '7fffffff'


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>Comment By: Martin v. Löwis (loewis)
Date: 2004-08-05 17:12

Message:
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The OverflowErrors are definitely intentional, and by
design. xrange() is documented as working the same way as
range(), so any error in the documentation is an error in
the range() documentation.

Reclassifying this as a documentation bug.

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Comment By: Raymond Hettinger (rhettinger)
Date: 2004-08-05 15:49

Message:
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user_id=80475

Do you have a real use case for this?  Do any real apps need
to loop over more than sys.maxint integers?  It would be
ashamed to muckup the high performance implementation for
something that does not arise in practice.

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