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Frame(range) may produce wrong result, rarely #1942

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st-pasha opened this issue Jul 31, 2019 · 0 comments · Fixed by #1943
Closed

Frame(range) may produce wrong result, rarely #1942

st-pasha opened this issue Jul 31, 2019 · 0 comments · Fixed by #1943
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@st-pasha
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bug Any bugs / errors in datatable; however for severe bugs use [segfault] label low priority Low priority tasks
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Release 0.10.0

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@st-pasha
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In some degenerate cases datatable miscalculates the number of elements in a range, returning a 1-row Frame instead of 0-row.

>>> dt.Frame(range(2, 2, 2)).to_list()
[[2]]
>>> list(range(2, 2, 2))
[]
@st-pasha st-pasha added bug Any bugs / errors in datatable; however for severe bugs use [segfault] label low priority Low priority tasks labels Jul 31, 2019
@st-pasha st-pasha added this to the Release 0.10.0 milestone Jul 31, 2019
@st-pasha st-pasha self-assigned this Jul 31, 2019
@st-pasha st-pasha mentioned this issue Jul 31, 2019
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st-pasha added a commit that referenced this issue Jul 31, 2019
@st-pasha
Fix Frame creation from a degenerate range (#1943)
c804581 
The length of range object was incorrectly interpreted when `start-step < stop <= start`. This was due to C division rules for negative numbers different from Python rules.

In addition, `Column::make_range()` was moved to `OColumn` class.

Closes #1942
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bug Any bugs / errors in datatable; however for severe bugs use [segfault] label low priority Low priority tasks
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Release 0.10.0
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Fix Frame creation from a degenerate range h2oai/datatable
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