BUG: pd.Series.duplicated/pd.core.algorithms.duplicated fails with float-based SparseArray

[tehunter]

Pandas version checks

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

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

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

>>> import pandas as pd
>>> import numpy as np
>>> arr = pd.arrays.SparseArray([0,1,np.nan,1])
>>> pd.core.algorithms.duplicated(arr)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/pandas/pandas/core/algorithms.py", line 1063, in duplicated
    values = _ensure_data(values)
  File "/home/pandas/pandas/core/algorithms.py", line 177, in _ensure_data
    if values.dtype.itemsize in [2, 12, 16]:  # type: ignore[union-attr]
AttributeError: 'SparseDtype' object has no attribute 'itemsize'

Same thing happens with pd.Series(arr).duplicated()

Issue Description

_ensure_data tries to access dtype.itemsize for float types. SparseArray can be considered a float type, but doesn't implement an itemsize attribute. Addressing #48424 may solve this, but the itemsize attribute is also causing an issue in #42070

Expected Behavior

Returns without error

Installed Versions

INSTALLED VERSIONS

commit : 24da5be
python : 3.8.13.final.0
python-bits : 64
OS : Linux
OS-release :
Version : #1 SMP Wed Mar 2 00:30:59 UTC 2022
machine : x86_64
processor : x86_64
byteorder : little
LC_ALL : C.UTF-8
LANG : C.UTF-8
LOCALE : en_US.UTF-8

pandas : 1.6.0.dev0+203.g24da5be949.dirty
numpy : 1.22.4
pytz : 2022.2.1
dateutil : 2.8.2
setuptools : 65.3.0
pip : 22.2.2
Cython : 0.29.32
pytest : 7.1.3
hypothesis : 6.54.6
sphinx : 4.5.0
blosc : None
feather : None
xlsxwriter : 3.0.3
lxml.etree : 4.9.1
html5lib : 1.1
pymysql : 1.0.2
psycopg2 : 2.9.3
jinja2 : 3.0.3
IPython : 8.5.0
pandas_datareader: 0.10.0
bs4 : 4.11.1
bottleneck : 1.3.5
brotli :
fastparquet : 0.8.3
fsspec : 2021.11.0
gcsfs : 2021.11.0
matplotlib : 3.6.0
numba : 0.55.2
numexpr : 2.8.3
odfpy : None
openpyxl : 3.0.10
pandas_gbq : 0.17.8
pyarrow : 9.0.0
pyreadstat : 1.1.9
pyxlsb : 1.0.9
s3fs : 2021.11.0
scipy : 1.9.1
snappy :
sqlalchemy : 1.4.41
tables : 3.7.0
tabulate : 0.8.10
xarray : 2022.6.0
xlrd : 2.0.1
xlwt : 1.3.0
zstandard : 0.18.0
tzdata : None

[EarsAndEggs]

Greetings, I'm also having the same issue where it says that AttributeError: 'SparseDtype' object has no attribute 'itemsize'

This is how I'm currently generating the dataframe, and trying to use HDFStore obviously won't work with the error

mat = pd.DataFrame.sparse.from_spmatrix(sparse_matrix, columns=column_names)
store = pd.HDFStore('sparse_matrix.h5')
store.put('mutation_matrix', mat, format='table', data_columns=True)
store.close()

Are there any updates on fixes?

[topper-123]

I can confirm this bug. A PR would be welcome.