[jira] [Created] (SPARK-23018) PySpark creatDataFrame causes Pandas warning of assignment to a copy of a reference

["Bryan Cutler (JIRA)" <ji...@apache.org>]

Bryan Cutler created SPARK-23018:
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             Summary: PySpark creatDataFrame causes Pandas warning of assignment to a copy of a reference
                 Key: SPARK-23018
                 URL: https://issues.apache.org/jira/browse/SPARK-23018
             Project: Spark
          Issue Type: Bug
          Components: PySpark
    Affects Versions: 2.3.0
            Reporter: Bryan Cutler


When calling {{SparkSession.createDataFrame}} with a Pandas DataFrame as input (with Arrow disabled) a Pandas warning is raised when the DataFrame is a slice:

{noformat}
In [1]: import numpy as np
   ...: import pandas as pd
   ...: pdf = pd.DataFrame(np.random.rand(100, 2))
   ...: 

In [2]: df = spark.createDataFrame(pdf[:10])
/home/bryan/git/spark/python/pyspark/sql/session.py:476: SettingWithCopyWarning: 
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead

See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
  pdf[column] = s
{noformat}

This doesn't seem to cause a bug in this case, but might for others.  It could be avoided by only assigning the series if it was a modified timestamp field.



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