BUG: Index._searchsorted_monotonic(..., side='right') returns the left side position for monotonic decreasing indexes · Issue #17271 · pandas-dev/pandas (original) (raw)

Code Sample, a copy-pastable example if possible

In [1]: import pandas as pd ...: idx = pd.Index([3, 2, 1]) ...: idx ...: Out[1]: Int64Index([3, 2, 1], dtype='int64')

In [2]: idx._searchsorted_monotonic(3, side='right') Out[2]: 0

In [3]: idx._searchsorted_monotonic(2, side='right') Out[3]: 1

In [4]: idx._searchsorted_monotonic(1, side='right') Out[4]: 2

Problem description

The left side positions are returned even though side='right' is specified.

Note that this is also the root cause of #16417

Expected Output

I'd expect the output to be 1, 2, 3 instead of 0, 1, 2.

Output of `pd.show_versions()`

INSTALLED VERSIONS

commit: None
python: 3.6.2.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