Closed
Description
Code Sample, a copy-pastable example
import pandas as pd
import scipy as sp
import scipy.sparse
spmatrix = sp.sparse.csr_matrix((2, 2))
spmatrix[0, 0] = 1
df = pd.DataFrame.sparse.from_spmatrix(spmatrix)
# work as expected, cool
df.loc[1]
# 0 0.0
# 1 0.0
# Name: 0, dtype: Sparse[float64, 0.0]
# Indexing by index list. I expect 1,0, 0.0, not cool
df.loc[[1]]
# 0 1
# 1 0.0 0
# whenever indexing an all-zero series, it returns int type.
df.loc[[1]].loc[[1]]
# 0 1
# 1 0 0
# checking the dtype, it has been turned into int64 instead of float64
df.loc[[1]].dtypes
# 0 Sparse[float64, 0]
# 1 Sparse[int64, 0]
# dtype: object
# indexing by bool list also not cool
df.loc[[True, True]]
# 0 1
# 0 1.0 0
# 1 0.0 0
# Slicing is cool
df.loc[0:2]
# 0 1
# 0 1.0 0.0
# 1 0.0 0.0
# If we explicitly specify its dtype, the type still not preserved.
import numpy as np
df.astype(np.float32).dtypes
# 0 Sparse[float32, 0.0]
# 1 Sparse[float32, 0.0]
df.astype(np.float32).loc[[1]].dtypes
# 0 Sparse[float64, 0.0]
# 1 Sparse[float64, 0.0]Problem description
Index slice an all-zero sparse series by indexer (whether by bool array or index array) results in type int64. It should preserve type.
Expected Output
Output of pd.show_versions()
INSTALLED VERSIONS
------------------
commit : 57034774bc16958b085ad6ca6d5379b9ac0289b3
python : 3.8.1.final.0
python-bits : 64
OS : Linux
OS-release : 4.15.0-101-generic
Version : #102-Ubuntu SMP Mon May 11 10:07:26 UTC 2020
machine : x86_64
processor : x86_64
byteorder : little
LC_ALL : en_US.UTF-8
LANG : en_US.UTF-8
LOCALE : en_US.UTF-8
pandas : 1.1.0.dev0+1742.g5703477
numpy : 1.18.4
pytz : 2020.1
dateutil : 2.8.1
pip : 20.1.1
setuptools : 41.2.0
Cython : 0.29.19
pytest : 5.4.3
hypothesis : 5.16.0
sphinx : 3.0.4
blosc : 1.9.1
feather : None
xlsxwriter : 1.2.9
lxml.etree : 4.5.1
html5lib : 1.0.1
pymysql : None
psycopg2 : None
jinja2 : 2.11.2
IPython : 7.15.0
pandas_datareader: None
bs4 : 4.9.1
bottleneck : 1.3.2
fastparquet : 0.4.0
gcsfs : None
matplotlib : 3.2.1
numexpr : 2.7.1
odfpy : None
openpyxl : 3.0.3
pandas_gbq : None
pyarrow : 0.17.1
pytables : None
pyxlsb : None
s3fs : 0.4.2
scipy : 1.4.1
sqlalchemy : 1.3.17
tables : 3.6.1
tabulate : 0.8.7
xarray : 0.15.1
xlrd : 1.2.0
xlwt : 1.3.0
numba : 0.49.1