BUG: qcut fails with Float64Dtype

[tamargrey]

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• (optional) I have confirmed this bug exists on the master branch of pandas.

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Code Sample, a copy-pastable example

series = pd.Series([1.0, 2.0, 3.0, 4.4], dtype=pd.Float64Dtype())
pd.qcut(series, 2)

Problem description

pd.qcut currently accepts the nullable Int64Dtype as well as 'float64', so I would expect it to work with the Float64Dtype as well. Instead the following error is produced:

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-29-1db98f70db38> in <module>
      1 series = pd.Series([1.0,2.0,3.0,4.0], dtype=pd.Float64Dtype())
----> 2 pd.qcut(series, 2)

~/.pyenv/versions/3.8.2/envs/woodwork/lib/python3.8/site-packages/pandas/core/reshape/tile.py in qcut(x, q, labels, retbins, precision, duplicates)
    356         quantiles = q
    357     bins = algos.quantile(x, quantiles)
--> 358     fac, bins = _bins_to_cuts(
    359         x,
    360         bins,

~/.pyenv/versions/3.8.2/envs/woodwork/lib/python3.8/site-packages/pandas/core/reshape/tile.py in _bins_to_cuts(x, bins, right, labels, precision, include_lowest, dtype, duplicates, ordered)
    408 
    409     if include_lowest:
--> 410         ids[x == bins[0]] = 1
    411 
    412     na_mask = isna(x) | (ids == len(bins)) | (ids == 0)

IndexError: only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices

Expected Output

Should match that of float64

0    (0.999, 2.5]
1    (0.999, 2.5]
2      (2.5, 4.0]
3      (2.5, 4.0]
dtype: category
Categories (2, interval[float64]): [(0.999, 2.5] < (2.5, 4.0]]

Output of pd.show_versions()

INSTALLED VERSIONS

commit : f2c8480
python : 3.8.2.final.0
python-bits : 64
OS : Darwin
OS-release : 19.6.0
Version : Darwin Kernel Version 19.6.0: Sun Jul 5 00:43:10 PDT 2020; root:xnu-6153.141.1~9/RELEASE_X86_64
machine : x86_64
processor : i386
byteorder : little
LC_ALL : None
LANG : en_US.UTF-8
LOCALE : en_US.UTF-8

pandas : 1.2.3
numpy : 1.19.5
pytz : 2021.1
dateutil : 2.8.1
pip : 21.0.1
setuptools : 41.2.0
Cython : None
pytest : 6.0.1
hypothesis : None
sphinx : 3.2.1
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 2.11.3
IPython : 7.18.1
pandas_datareader: None
bs4 : None
bottleneck : None
fsspec : 0.8.7
fastparquet : None
gcsfs : None
matplotlib : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : 3.0.0
pyxlsb : None
s3fs : None
scipy : 1.6.2
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
xlwt : None
numba : None

[jorisvandenbossche]

@tamargrey Thanks for the report!

This was fixed last year for the nullable Int64Dtype in #31440, but it seems we need to generalize the fix to also cover Float64Dtype.

In this location:

pandas/pandas/core/reshape/tile.py

Lines 482 to 487 in 5c64037

	# To support cut and qcut for IntegerArray we convert to float dtype.
	# Will properly support in the future.
	# https://github.com/pandas-dev/pandas/pull/31290
	# https://github.com/pandas-dev/pandas/issues/31389
	elif is_extension_array_dtype(x.dtype) and is_integer_dtype(x.dtype):
	x = x.to_numpy(dtype=np.float64, na_value=np.nan)

we need to change the is_integer_dtype to generally catch nullable numeric dtypes

[lithomas1]

Fixed by #40969