IntervalIndex is_non_overlapping_monotonic is incorrect when endpoints are shared · Issue #16560 · pandas-dev/pandas (original) (raw)

Code Sample, a copy-pastable example if possible

In [2]: idx = pd.IntervalIndex.from_breaks(range(4), closed='both')

In [3]: idx Out[3]: IntervalIndex([[0, 1], [1, 2], [2, 3]] closed='both', dtype='interval[int64]')

In [4]: idx.is_non_overlapping_monotonic Out[4]: True

Problem description

The intervals have an overlap in the endpoints, 1 is shared among [0, 1], [1, 2] and 2 is shared among [1, 2], [2, 3], but is_non_overlapping_monotonic returns True indicating that the intervals are non-overlapping.

Expected Output

I'd expected is_non_overlapping_monotonic to return False.

If my interpretation of "overlapping" is incorrect, and in this context means an interval overlap (i.e. not a point/has positive length), then it'd be nice if this were more explicitly stated.

Output of `pd.show_versions()`

INSTALLED VERSIONS

commit: None
python: 3.5.2.final.0
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 78 Stepping 3, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None