From b66afdeb5253913d916dcf159aaed4ffdc15fd4b Mon Sep 17 00:00:00 2001
From: Holden Karau <holden@us.ibm.com>
Date: Mon, 25 Jan 2016 22:38:31 -0800
Subject: [PATCH] [SPARK-11922][PYSPARK][ML] Python api for ml.feature.quantile
discretizer
Add Python API for ml.feature.QuantileDiscretizer.
One open question: Do we want to do this stuff to re-use the java model, create a new model, or use a different wrapper around the java model.
cc brkyvz & mengxr
Author: Holden Karau <holden@us.ibm.com>
Closes #10085 from holdenk/SPARK-11937-SPARK-11922-Python-API-for-ml.feature.QuantileDiscretizer.
---
python/pyspark/ml/feature.py | 89 ++++++++++++++++++++++++++++++++++--
1 file changed, 85 insertions(+), 4 deletions(-)
diff --git a/python/pyspark/ml/feature.py b/python/pyspark/ml/feature.py
index 1fa0eab384..f139d81bc4 100644
--- a/python/pyspark/ml/feature.py
+++ b/python/pyspark/ml/feature.py
@@ -30,10 +30,10 @@ from pyspark.mllib.linalg import _convert_to_vector
__all__ = ['Binarizer', 'Bucketizer', 'CountVectorizer', 'CountVectorizerModel', 'DCT',
'ElementwiseProduct', 'HashingTF', 'IDF', 'IDFModel', 'IndexToString', 'MinMaxScaler',
'MinMaxScalerModel', 'NGram', 'Normalizer', 'OneHotEncoder', 'PCA', 'PCAModel',
- 'PolynomialExpansion', 'RegexTokenizer', 'RFormula', 'RFormulaModel', 'SQLTransformer',
- 'StandardScaler', 'StandardScalerModel', 'StopWordsRemover', 'StringIndexer',
- 'StringIndexerModel', 'Tokenizer', 'VectorAssembler', 'VectorIndexer', 'VectorSlicer',
- 'Word2Vec', 'Word2VecModel']
+ 'PolynomialExpansion', 'QuantileDiscretizer', 'RegexTokenizer', 'RFormula',
+ 'RFormulaModel', 'SQLTransformer', 'StandardScaler', 'StandardScalerModel',
+ 'StopWordsRemover', 'StringIndexer', 'StringIndexerModel', 'Tokenizer',
+ 'VectorAssembler', 'VectorIndexer', 'VectorSlicer', 'Word2Vec', 'Word2VecModel']
@inherit_doc
@@ -991,6 +991,87 @@ class PolynomialExpansion(JavaTransformer, HasInputCol, HasOutputCol):
return self.getOrDefault(self.degree)
+@inherit_doc
+class QuantileDiscretizer(JavaEstimator, HasInputCol, HasOutputCol):
+ """
+ .. note:: Experimental
+
+ `QuantileDiscretizer` takes a column with continuous features and outputs a column with binned
+ categorical features. The bin ranges are chosen by taking a sample of the data and dividing it
+ into roughly equal parts. The lower and upper bin bounds will be -Infinity and +Infinity,
+ covering all real values. This attempts to find numBuckets partitions based on a sample of data,
+ but it may find fewer depending on the data sample values.
+
+ >>> df = sqlContext.createDataFrame([(0.1,), (0.4,), (1.2,), (1.5,)], ["values"])
+ >>> qds = QuantileDiscretizer(numBuckets=2,
+ ... inputCol="values", outputCol="buckets")
+ >>> bucketizer = qds.fit(df)
+ >>> splits = bucketizer.getSplits()
+ >>> splits[0]
+ -inf
+ >>> print("%2.1f" % round(splits[1], 1))
+ 0.4
+ >>> bucketed = bucketizer.transform(df).head()
+ >>> bucketed.buckets
+ 0.0
+
+ .. versionadded:: 2.0.0
+ """
+
+ # a placeholder to make it appear in the generated doc
+ numBuckets = Param(Params._dummy(), "numBuckets",
+ "Maximum number of buckets (quantiles, or " +
+ "categories) into which data points are grouped. Must be >= 2. Default 2.")
+
+ @keyword_only
+ def __init__(self, numBuckets=2, inputCol=None, outputCol=None):
+ """
+ __init__(self, numBuckets=2, inputCol=None, outputCol=None)
+ """
+ super(QuantileDiscretizer, self).__init__()
+ self._java_obj = self._new_java_obj("org.apache.spark.ml.feature.QuantileDiscretizer",
+ self.uid)
+ self.numBuckets = Param(self, "numBuckets",
+ "Maximum number of buckets (quantiles, or " +
+ "categories) into which data points are grouped. Must be >= 2.")
+ self._setDefault(numBuckets=2)
+ kwargs = self.__init__._input_kwargs
+ self.setParams(**kwargs)
+
+ @keyword_only
+ @since("2.0.0")
+ def setParams(self, numBuckets=2, inputCol=None, outputCol=None):
+ """
+ setParams(self, numBuckets=2, inputCol=None, outputCol=None)
+ Set the params for the QuantileDiscretizer
+ """
+ kwargs = self.setParams._input_kwargs
+ return self._set(**kwargs)
+
+ @since("2.0.0")
+ def setNumBuckets(self, value):
+ """
+ Sets the value of :py:attr:`numBuckets`.
+ """
+ self._paramMap[self.numBuckets] = value
+ return self
+
+ @since("2.0.0")
+ def getNumBuckets(self):
+ """
+ Gets the value of numBuckets or its default value.
+ """
+ return self.getOrDefault(self.numBuckets)
+
+ def _create_model(self, java_model):
+ """
+ Private method to convert the java_model to a Python model.
+ """
+ return Bucketizer(splits=list(java_model.getSplits()),
+ inputCol=self.getInputCol(),
+ outputCol=self.getOutputCol())
+
+
@inherit_doc
@ignore_unicode_prefix
class RegexTokenizer(JavaTransformer, HasInputCol, HasOutputCol):
--
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