Erratic behavior using query() and timedelta

Code Sample, a copy-pastable example if possible

import pandas as pd
d = pd.DataFrame([pd.Timedelta(5,'D')], columns=['dt'])
d.query('dt =="5 days"', engine='numexpr')
# works: 
#      dt
# 0 5 days

d.query('dt =="4 days"', engine='numexpr')
# works:
#Empty DataFrame
#Columns: [dt]
#Index: []

d.query('dt <"5 days"', engine='numexpr')
# Does not work
# ValueError: unknown type timedelta64[ns]

Problem description

Using query on timedelta values has erratic behavior, and was working before. I can’t see how suddenly, less than, and greater than operations using query do not work, but == does.

Expected Output

import pandas as pd
d = pd.DataFrame([pd.Timedelta(5,'D')], columns=['dt'])


d.query('dt <"5 days"')
#EXPECTED:
#      dt
# 0 5 days`

INSTALLED VERSIONS

commit: None python: 3.7.0.final.0 python-bits: 64 OS: Darwin OS-release: 17.7.0 machine: x86_64 processor: i386 byteorder: little LC_ALL: None LANG: en_US.UTF-8 LOCALE: en_US.UTF-8

pandas: 0.23.4 pytest: None pip: 18.1 setuptools: 39.2.0 Cython: 0.28.3 numpy: 1.14.5 scipy: 1.1.0 pyarrow: None xarray: None IPython: 6.4.0 sphinx: None patsy: 0.5.0 dateutil: 2.7.3 pytz: 2018.5 blosc: None bottleneck: 1.2.1 tables: None numexpr: 2.6.8 feather: None matplotlib: 2.2.2 openpyxl: 2.5.9 xlrd: 1.1.0 xlwt: None xlsxwriter: 1.1.2 lxml: 4.2.5 bs4: None html5lib: 1.0.1 sqlalchemy: None pymysql: None psycopg2: 2.7.5 (dt dec pq3 ext lo64) jinja2: 2.10 s3fs: None fastparquet: None pandas_gbq: None pandas_datareader: 0.7.0

[gfyoung]

So I’m able to reproduce, but you need to have numexpr installed. Just not sure which pandas version you had installed though…

@jsevo : To work around this, pass in engine='python'.

[gfyoung]

I went back a couple of year’s worth of releases, but I can’t seem to find a combo of pandas and numexpr that gets the example to work…very strange…

@jsevo : if you’re able to retrieve your old environment information, that would be great!