Support DataFrame parameter in Series.dot

[xinrong-meng]

No description provided.

[ueshin]

Could you add an example using DataFrame in the docstring?

[codecov-io]

Codecov Report

Merging #1931 (10127ac) into master (8d35a74) will increase coverage by 0.13%.
The diff coverage is 88.23%.

@@            Coverage Diff             @@
##           master    #1931      +/-   ##
==========================================
+ Coverage   94.50%   94.63%   +0.13%     
==========================================
  Files          45       49       +4     
  Lines       10682    10829     +147     
==========================================
+ Hits        10095    10248     +153     
+ Misses        587      581       -6     

Impacted Files	Coverage Δ
databricks/koalas/series.py	96.87% <88.23%> (-0.17%)	⬇️
databricks/koalas/utils.py	95.71% <0.00%> (ø)
databricks/koalas/groupby.py	91.42% <0.00%> (ø)
databricks/koalas/indexing.py	92.62% <0.00%> (ø)
databricks/koalas/namespace.py	84.23% <0.00%> (ø)
databricks/koalas/spark/accessors.py	94.96% <0.00%> (ø)
databricks/koalas/tests/plot/test_series_plot.py	100.00% <0.00%> (ø)
databricks/koalas/plot.py
databricks/koalas/plot/core.py	92.77% <0.00%> (ø)
databricks/koalas/plot/__init__.py	100.00% <0.00%> (ø)
... and 7 more

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[ueshin]

Shall we add a type annotation for the argument other?

[ueshin]

Could you add more tests like:

pdf = pd.DataFrame({"a": [1, 2, 3], "b": [4, 5, 6]})
kdf = ks.from_pandas(pdf)

self.assert_eq((pdf['b'] * 10).dot(pdf['a']), ...)
self.assert_eq((pdf['b'] * 10).dot(pdf), ...)
self.assert_eq((pdf['b'] * 10).dot(pdf + 1), ...)

[itholic]

Otherwise, seems good to me.

[ueshin]

LGTM.

[ueshin]

Thanks! I'd merge this now.

[xinrong-meng]

Thank you!