Error using df.index in and condition #3227
Description
When trying to filter on the index and another condition I get a ValueError: 'dtype' inference failed in 'elemwise' error. The identical condition works in pandas. Issue seems related to the fact that df.index returns a dask array. On dask 0.17.1.
Example
import pandas as pd
import dask.dataframe as dd
df = pd.DataFrame({'time': pd.date_range('2018-01-01', periods=10),
'mycat': list('ABCABCABCA')})
df = df.set_index('time')
df['mycat'] = df.mycat.astype('category')
(df.index > '2018-01-01') & (df.mycat == 'A')
ddf = dd.from_pandas(df, npartitions=2)
(ddf.index > '2018-01-01') & (ddf.mycat == 'A')
Stacktrace
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-7-11ce8cc93904> in <module>()
8 (df.index > '2018-01-01') & (df.mycat == 'A')
9 ddf = dd.from_pandas(df, npartitions=2)
---> 10 (ddf.index > '2018-01-01') & (ddf.mycat == 'A')
11 # (ddf.mycat == 'A') & (ddf.index > '2018-01-01')
~/anaconda3/envs/cme/lib/python3.6/site-packages/dask/array/core.py in __and__(self, other)
1455
1456 def __and__(self, other):
-> 1457 return elemwise(operator.and_, self, other)
1458
1459 def __rand__(self, other):
~/anaconda3/envs/cme/lib/python3.6/site-packages/dask/array/core.py in elemwise(op, *args, **kwargs)
2935 if not is_scalar_for_elemwise(a) else a
2936 for a in args]
-> 2937 dt = apply_infer_dtype(op, vals, {}, 'elemwise', suggest_dtype=False)
2938 need_enforce_dtype = any(not is_scalar_for_elemwise(a) and a.ndim == 0 for a in args)
2939
~/anaconda3/envs/cme/lib/python3.6/site-packages/dask/array/core.py in apply_infer_dtype(func, args, kwargs, funcname, suggest_dtype)
544 msg = None
545 if msg is not None:
--> 546 raise ValueError(msg)
547 return o.dtype
548
ValueError: `dtype` inference failed in `elemwise`.
Original error is below:
------------------------
AttributeError("'numpy.ndarray' object has no attribute 'index'",)
Traceback:
---------
File "/Users/rpostelnik/anaconda3/envs/cme/lib/python3.6/site-packages/dask/array/core.py", line 529, in apply_infer_dtype
o = func(*args, **kwargs)
File "/Users/rpostelnik/anaconda3/envs/cme/lib/python3.6/site-packages/dask/dataframe/core.py", line 1706, in __array_wrap__
index = context[1][0].index