[IronPython] in operator calls __getitem__ on class that has __len__ and __iter__ defined

Dino Viehland dinov at microsoft.com
Thu Nov 20 18:13:14 CET 2008

Oh, on the formatting - CodePlex actually preserves the white space it just doesn't display it.  It's annoying but I'm not aware of a way to make it actually display other than clicking Edit which I think only we can do :(.

From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Glenn Jones
Sent: Thursday, November 20, 2008 7:23 AM
To: users at lists.ironpython.com
Subject: [IronPython] in operator calls __getitem__ on class that has __len__ and __iter__ defined

Yet another weirdness, but not a blocker for us:

With this object:

class o(object):
  def __iter__(self):
    print "iter"
    return iter([1, 2, 3])
  def __getitem__(self, index):
    print "getitem"
    return [1, 2, 3][index]
  def __len__(self):
    print "len"
    return 3

>>> p = o()
>>> 1 in p

IronPython 2 source drop 43741:
>>> p = o()
>>> 1 in p

It looks like CPython is treating it like a sequence and IronPython 2 is treating it like a dict.

We have worked around this by implementing __contains__

Raised as Issue 19678 on CodePlex.

PS: How can we format code blocks on CodePlex?

Glenn & Orestis
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