diff options
Diffstat (limited to 'python/pyspark/sql/dataframe.py')
-rw-r--r-- | python/pyspark/sql/dataframe.py | 36 |
1 files changed, 35 insertions, 1 deletions
diff --git a/python/pyspark/sql/dataframe.py b/python/pyspark/sql/dataframe.py index 5908ebc990..1f08c2df93 100644 --- a/python/pyspark/sql/dataframe.py +++ b/python/pyspark/sql/dataframe.py @@ -34,7 +34,8 @@ from pyspark.sql.types import * from pyspark.sql.types import _create_cls, _parse_datatype_json_string -__all__ = ["DataFrame", "GroupedData", "Column", "SchemaRDD", "DataFrameNaFunctions"] +__all__ = ["DataFrame", "GroupedData", "Column", "SchemaRDD", "DataFrameNaFunctions", + "DataFrameStatFunctions"] class DataFrame(object): @@ -93,6 +94,12 @@ class DataFrame(object): """ return DataFrameNaFunctions(self) + @property + def stat(self): + """Returns a :class:`DataFrameStatFunctions` for statistic functions. + """ + return DataFrameStatFunctions(self) + @ignore_unicode_prefix def toJSON(self, use_unicode=True): """Converts a :class:`DataFrame` into a :class:`RDD` of string. @@ -868,6 +875,20 @@ class DataFrame(object): return DataFrame(self._jdf.na().fill(value, self._jseq(subset)), self.sql_ctx) + def cov(self, col1, col2): + """ + Calculate the sample covariance for the given columns, specified by their names, as a + double value. :func:`DataFrame.cov` and :func:`DataFrameStatFunctions.cov` are aliases. + + :param col1: The name of the first column + :param col2: The name of the second column + """ + if not isinstance(col1, str): + raise ValueError("col1 should be a string.") + if not isinstance(col2, str): + raise ValueError("col2 should be a string.") + return self._jdf.stat().cov(col1, col2) + @ignore_unicode_prefix def withColumn(self, colName, col): """Returns a new :class:`DataFrame` by adding a column. @@ -1311,6 +1332,19 @@ class DataFrameNaFunctions(object): fill.__doc__ = DataFrame.fillna.__doc__ +class DataFrameStatFunctions(object): + """Functionality for statistic functions with :class:`DataFrame`. + """ + + def __init__(self, df): + self.df = df + + def cov(self, col1, col2): + return self.df.cov(col1, col2) + + cov.__doc__ = DataFrame.cov.__doc__ + + def _test(): import doctest from pyspark.context import SparkContext |