Description
>>> from pandas import *
>>> from numpy.random import randn
>>>
>>> df = DataFrame(randn(20, 4))
>>> df = df.applymap(lambda x: np.nan if x > 0 else x)
>>> sparse_df = df.to_sparse(fill_value=0.35)
>>> sparse_df
0 1 2 3
0 -1.101095 NaN -1.512058 -0.283055
1 -0.460331 NaN -0.995369 NaN
2 NaN -0.835043 -1.367358 -0.950400
3 -0.704320 -0.746556 -0.389821 NaN
4 NaN -0.573624 NaN -1.033302
5 NaN NaN -1.684434 -1.805903
6 NaN NaN NaN NaN
7 -0.129019 -2.279948 -0.229312 -0.725433
8 -1.264768 -0.050307 NaN -0.453808
9 -0.976076 -0.127872 -0.794526 NaN
10 -0.126079 -0.774120 -0.424461 -0.061588
11 -0.474522 NaN -0.437307 -0.727405
12 NaN -0.883299 NaN -1.435336
13 -1.588188 NaN -1.740614 -0.645563
14 -1.218019 NaN NaN -0.341365
15 -0.522648 -1.377164 NaN NaN
16 NaN -1.193746 -1.295383 NaN
17 -1.445435 -0.034316 -0.879550 -1.570954
18 NaN -0.060612 NaN NaN
19 NaN NaN -0.009722 NaN
Problem description
I've looked at issues log and don't seem to find an issue regarding this. It appears that DataFrame.to_sparse keyword fill_value which subsequently injected into SparseDataFrame doesn't seem to do anything.
Is it actually a bug or the documentation isn't accurate enough?
Expected Output
0 1 2 3
0 -1.101095 0.350000 -1.512058 -0.283055
1 -0.460331 0.350000 -0.995369 0.350000
2 0.350000 -0.835043 -1.367358 -0.950400
3 -0.704320 -0.746556 -0.389821 0.350000
4 0.350000 -0.573624 0.350000 -1.033302
5 0.350000 0.350000 -1.684434 -1.805903
6 0.350000 0.350000 0.350000 0.350000
7 -0.129019 -2.279948 -0.229312 -0.725433
8 -1.264768 -0.050307 0.350000 -0.453808
9 -0.976076 -0.127872 -0.794526 0.350000
10 -0.126079 -0.774120 -0.424461 -0.061588
11 -0.474522 0.350000 -0.437307 -0.727405
12 0.350000 -0.883299 0.350000 -1.435336
13 -1.588188 0.350000 -1.740614 -0.645563
14 -1.218019 0.350000 0.350000 -0.341365
15 -0.522648 -1.377164 0.350000 0.350000
16 0.350000 -1.193746 -1.295383 0.350000
17 -1.445435 -0.034316 -0.879550 -1.570954
18 0.350000 -0.060612 0.350000 0.350000
19 0.350000 0.350000 -0.009722 0.350000
Output of pd.show_versions()
INSTALLED VERSIONS
commit: None
python: 3.6.1.final.0
python-bits: 64
OS: Darwin
OS-release: 17.4.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: en_GB.UTF-8
LOCALE: en_GB.UTF-8
pandas: 0.22.0
pytest: None
pip: 9.0.1
setuptools: 36.3.0
Cython: None
numpy: 1.14.1
scipy: 0.19.1
pyarrow: None
xarray: None
IPython: 5.3.0
sphinx: None
patsy: 0.4.1
dateutil: 2.6.1
pytz: 2018.3
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: 2.0.0
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: 4.5.3
html5lib: 0.9999999
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.9.6
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None