#18378: list(ZZ) --> infinite loop
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Reporter: | Owner:
ncohen | Status: needs_review
Type: | Milestone: sage-6.7
defect | Resolution:
Priority: major | Merged in:
Component: basic | Reviewers:
arithmetic | Work issues:
Keywords: | Commit:
Authors: | 9ba72b347c17cf60cd7d5f0f7cda9185c33f9fa0
Nathann Cohen | Stopgaps:
Report Upstream: N/A |
Branch: |
public/18378 |
Dependencies: |
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Comment (by nbruin):
For posterity, the reason that `TypeError` gets caught is to make this
work:
{{{
sage: l=(i for i in range(10))
sage: len(l)
TypeError: object of type 'generator' has no len()
sage: list(l)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
}}}
It may well be an accident that `list` checks `len` of its argument before
it checks if it's iterable, so I would not consider changing the error
type a reliable way to prevent an infinite loop. I don't think python
officially supports a way of preventing `list(<infinite iterable>)` from
going in an infinite loop. It works, though...
--
Ticket URL: <http://trac.sagemath.org/ticket/18378#comment:4>
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