[SPARK-35071][PYTHON] Rename Koalas to pandas-on-Spark in main codes

[HyukjinKwon]

What changes were proposed in this pull request?

This PR proposes to rename Koalas to pandas-on-Spark in main codes

Why are the changes needed?

To have the correct name in PySpark. NOTE that the official name in the main documentation will be pandas APIs on Spark to be extra clear. pandas-on-Spark is not the official term.

Does this PR introduce any user-facing change?

No, it's master-only change. It changes the docstring and class names.

How was this patch tested?

Manually tested via:

./python/run-tests --python-executable=python3 --modules pyspark-pandas

[HyukjinKwon]

cc @ueshin @xinrong-databricks @itholic

[SparkQA]

Test build #137344 has finished for PR 32166 at commit 4ca5c6d.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
• class PandasOnSparkFrameMethods(object):
• class PandasOnSparkSeriesMethods(object):
• class PandasOnSparkPlotAccessor(PandasObject):
• class PandasOnSparkBarPlot(PandasBarPlot, TopNPlotBase):
• class PandasOnSparkBoxPlot(PandasBoxPlot, BoxPlotBase):
• class PandasOnSparkHistPlot(PandasHistPlot, HistogramPlotBase):
• class PandasOnSparkPiePlot(PandasPiePlot, TopNPlotBase):
• class PandasOnSparkAreaPlot(PandasAreaPlot, SampledPlotBase):
• class PandasOnSparkLinePlot(PandasLinePlot, SampledPlotBase):
• class PandasOnSparkBarhPlot(PandasBarhPlot, TopNPlotBase):
• class PandasOnSparkScatterPlot(PandasScatterPlot, TopNPlotBase):
• class PandasOnSparkKdePlot(PandasKdePlot, KdePlotBase):
• class PandasOnSparkUsageLogger(object):

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/41923/

[SparkQA]

Kubernetes integration test status failure
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/41923/

[xinrong-meng]

LGTM, thanks!

May I confirm that the official name in the main documentation will be PySpark APIs on Spark(according to the PR description) rather than Pandas APIs on Spark?

[github-actions]

Test build #748086638 for PR 32166 at commit 4ca5c6d.

[itholic]

@xinrong-databricks I think Pandas APIs on Spark is correct. Maybe it's typo.

[itholic]

LGTM

[ueshin]

I can still see Koalas in the doc.

• https://github.com/apache/spark/blob/4ca5c6d5622c46b0947ee0ee4c0cb0b21829259e/python/pyspark/pandas/base.py#L216
• https://github.com/apache/spark/blob/4ca5c6d5622c46b0947ee0ee4c0cb0b21829259e/python/pyspark/pandas/frame.py#L4944
• https://github.com/apache/spark/blob/4ca5c6d5622c46b0947ee0ee4c0cb0b21829259e/python/pyspark/pandas/generic.py#L624
• https://github.com/apache/spark/blob/4ca5c6d5622c46b0947ee0ee4c0cb0b21829259e/python/pyspark/pandas/generic.py#L855
• https://github.com/apache/spark/blob/4ca5c6d5622c46b0947ee0ee4c0cb0b21829259e/python/pyspark/pandas/plot/core.py#L589
• https://github.com/apache/spark/blob/4ca5c6d5622c46b0947ee0ee4c0cb0b21829259e/python/pyspark/pandas/plot/core.py#L775
• https://github.com/apache/spark/blob/4ca5c6d5622c46b0947ee0ee4c0cb0b21829259e/python/pyspark/pandas/mlflow.py#L38
• https://github.com/apache/spark/blob/4ca5c6d5622c46b0947ee0ee4c0cb0b21829259e/python/pyspark/pandas/mlflow.py#L85

[HyukjinKwon]

Oops, I wonder how I missed so many instances ...

[github-actions]

Test build #750424771 for PR 32166 at commit c174c6f.

[ueshin]

LGTM.

[SparkQA]

Test build #137388 has finished for PR 32166 at commit c174c6f.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/41965/

[SparkQA]

Kubernetes integration test status failure
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/41965/

[HyukjinKwon]

Merged to master.