Apache Arrow 0.15.0 did not work well with PySpark 2.4 so it was disabled in the previous version. With Arrow 0.15.1, now it works in Koalas (#902).
We also added expanding() and rolling() APIs in all groupby(), Series and Frame (#985, #991, #990, #1015, #996, #1034, #1037)
expanding()
rolling()
groupby()
min
max
sum
mean
std
var
We continue improving multi-index columns support. We made the following APIs support multi-index columns:
median (#995)
median
at (#1049)
at
We added “Best Practices” section in the documentation (#1041) so that Koalas users can read and follow. Please see https://koalas.readthedocs.io/en/latest/user_guide/best_practices.html
We added the following new features:
koalas.DataFrame:
quantile (#984)
quantile
explain (#1042)
explain
koalas.Series:
between (#997)
between
update (#923)
update
mask (#1017)
mask
koalas.MultiIndex:
from_tuples (#970)
from_tuples
from_arrays (#1001)
from_arrays
Along with the following improvements:
Introduce column_scols in InternalFrame substitude for data_columns. (#956)
Fix different index level assignment when ‘compute.ops_on_diff_frames’ is enabled (#1045)
Fix Dataframe.melt function & Add doctest case for melt function (#987)
Enable creating Index from list like ‘Index([1, 2, 3])’ (#986)
Fix combine_frames to handle where the right hand side arguments are modified Series (#1020)
setup.py should support Python 2 to show a proper error message. (#1027)
setup.py
Remove Series.schema. (#993)
Series.schema