CountVectorizer¶

class pyspark.ml.feature.CountVectorizer(*, minTF=1.0, minDF=1.0, maxDF=9223372036854775807, vocabSize=262144, binary=False, inputCol=None, outputCol=None)[source]¶

Extracts a vocabulary from document collections and generates a CountVectorizerModel.

New in version 1.6.0.

Examples

>>> df = spark.createDataFrame(
...    [(0, ["a", "b", "c"]), (1, ["a", "b", "b", "c", "a"])],
...    ["label", "raw"])
>>> cv = CountVectorizer()
>>> cv.setInputCol("raw")
CountVectorizer...
>>> cv.setOutputCol("vectors")
CountVectorizer...
>>> model = cv.fit(df)
>>> model.setInputCol("raw")
CountVectorizerModel...
>>> model.transform(df).show(truncate=False)
+-----+---------------+-------------------------+
|label|raw            |vectors                  |
+-----+---------------+-------------------------+
|0    |[a, b, c]      |(3,[0,1,2],[1.0,1.0,1.0])|
|1    |[a, b, b, c, a]|(3,[0,1,2],[2.0,2.0,1.0])|
+-----+---------------+-------------------------+
...
>>> sorted(model.vocabulary) == ['a', 'b', 'c']
True
>>> countVectorizerPath = temp_path + "/count-vectorizer"
>>> cv.save(countVectorizerPath)
>>> loadedCv = CountVectorizer.load(countVectorizerPath)
>>> loadedCv.getMinDF() == cv.getMinDF()
True
>>> loadedCv.getMinTF() == cv.getMinTF()
True
>>> loadedCv.getVocabSize() == cv.getVocabSize()
True
>>> modelPath = temp_path + "/count-vectorizer-model"
>>> model.save(modelPath)
>>> loadedModel = CountVectorizerModel.load(modelPath)
>>> loadedModel.vocabulary == model.vocabulary
True
>>> loadedModel.transform(df).take(1) == model.transform(df).take(1)
True
>>> fromVocabModel = CountVectorizerModel.from_vocabulary(["a", "b", "c"],
...     inputCol="raw", outputCol="vectors")
>>> fromVocabModel.transform(df).show(truncate=False)
+-----+---------------+-------------------------+
|label|raw            |vectors                  |
+-----+---------------+-------------------------+
|0    |[a, b, c]      |(3,[0,1,2],[1.0,1.0,1.0])|
|1    |[a, b, b, c, a]|(3,[0,1,2],[2.0,2.0,1.0])|
+-----+---------------+-------------------------+
...

Methods

`clear`(param)	Clears a param from the param map if it has been explicitly set.
`copy`([extra])	Creates a copy of this instance with the same uid and some extra params.
`explainParam`(param)	Explains a single param and returns its name, doc, and optional default value and user-supplied value in a string.
`explainParams`()	Returns the documentation of all params with their optionally default values and user-supplied values.
`extractParamMap`([extra])	Extracts the embedded default param values and user-supplied values, and then merges them with extra values from input into a flat param map, where the latter value is used if there exist conflicts, i.e., with ordering: default param values < user-supplied values < extra.
`fit`(dataset[, params])	Fits a model to the input dataset with optional parameters.
`fitMultiple`(dataset, paramMaps)	Fits a model to the input dataset for each param map in paramMaps.
`getBinary`()	Gets the value of binary or its default value.
`getInputCol`()	Gets the value of inputCol or its default value.
`getMaxDF`()	Gets the value of maxDF or its default value.
`getMinDF`()	Gets the value of minDF or its default value.
`getMinTF`()	Gets the value of minTF or its default value.
`getOrDefault`(param)	Gets the value of a param in the user-supplied param map or its default value.
`getOutputCol`()	Gets the value of outputCol or its default value.
`getParam`(paramName)	Gets a param by its name.
`getVocabSize`()	Gets the value of vocabSize or its default value.
`hasDefault`(param)	Checks whether a param has a default value.
`hasParam`(paramName)	Tests whether this instance contains a param with a given (string) name.
`isDefined`(param)	Checks whether a param is explicitly set by user or has a default value.
`isSet`(param)	Checks whether a param is explicitly set by user.
`load`(path)	Reads an ML instance from the input path, a shortcut of read().load(path).
`read`()	Returns an MLReader instance for this class.
`save`(path)	Save this ML instance to the given path, a shortcut of ‘write().save(path)’.
`set`(param, value)	Sets a parameter in the embedded param map.
`setBinary`(value)	Sets the value of `binary`.
`setInputCol`(value)	Sets the value of `inputCol`.
`setMaxDF`(value)	Sets the value of `maxDF`.
`setMinDF`(value)	Sets the value of `minDF`.
`setMinTF`(value)	Sets the value of `minTF`.
`setOutputCol`(value)	Sets the value of `outputCol`.
`setParams`(self, \*[, minTF, minDF, maxDF, …])	Set the params for the CountVectorizer
`setVocabSize`(value)	Sets the value of `vocabSize`.
`write`()	Returns an MLWriter instance for this ML instance.

Attributes

`binary`
`inputCol`
`maxDF`
`minDF`
`minTF`
`outputCol`
`params`	Returns all params ordered by name.
`vocabSize`

Methods Documentation

clear(param)¶: Clears a param from the param map if it has been explicitly set.

copy(extra=None)¶

Creates a copy of this instance with the same uid and some extra params. This implementation first calls Params.copy and then make a copy of the companion Java pipeline component with extra params. So both the Python wrapper and the Java pipeline component get copied.

Parameters:

extradict, optional: Extra parameters to copy to the new instance

Returns:

JavaParams: Copy of this instance

explainParam(param)¶: Explains a single param and returns its name, doc, and optional default value and user-supplied value in a string.

explainParams()¶: Returns the documentation of all params with their optionally default values and user-supplied values.

extractParamMap(extra=None)¶

Extracts the embedded default param values and user-supplied values, and then merges them with extra values from input into a flat param map, where the latter value is used if there exist conflicts, i.e., with ordering: default param values < user-supplied values < extra.

Parameters:

extradict, optional: extra param values

Returns:

dict: merged param map

fit(dataset, params=None)¶

Fits a model to the input dataset with optional parameters.

New in version 1.3.0.

Parameters:

datasetpyspark.sql.DataFrame: input dataset.
paramsdict or list or tuple, optional: an optional param map that overrides embedded params. If a list/tuple of param maps is given, this calls fit on each param map and returns a list of models.

Returns:

Transformer or a list of Transformer: fitted model(s)

fitMultiple(dataset, paramMaps)¶

Fits a model to the input dataset for each param map in paramMaps.

New in version 2.3.0.

Parameters:

datasetpyspark.sql.DataFrame: input dataset.
paramMapscollections.abc.Sequence: A Sequence of param maps.

Returns:

_FitMultipleIterator: A thread safe iterable which contains one model for each param map. Each call to next(modelIterator) will return (index, model) where model was fit using paramMaps[index]. index values may not be sequential.

getBinary()¶: Gets the value of binary or its default value.

New in version 2.0.0.

getInputCol()¶: Gets the value of inputCol or its default value.

getMaxDF()¶: Gets the value of maxDF or its default value.

New in version 2.4.0.

getMinDF()¶: Gets the value of minDF or its default value.

New in version 1.6.0.

getMinTF()¶: Gets the value of minTF or its default value.

New in version 1.6.0.

getOrDefault(param)¶: Gets the value of a param in the user-supplied param map or its default value. Raises an error if neither is set.

getOutputCol()¶: Gets the value of outputCol or its default value.

getParam(paramName)¶: Gets a param by its name.

getVocabSize()¶: Gets the value of vocabSize or its default value.

New in version 1.6.0.

hasDefault(param)¶: Checks whether a param has a default value.

hasParam(paramName)¶: Tests whether this instance contains a param with a given (string) name.

isDefined(param)¶: Checks whether a param is explicitly set by user or has a default value.

isSet(param)¶: Checks whether a param is explicitly set by user.

classmethod load(path)¶: Reads an ML instance from the input path, a shortcut of read().load(path).

classmethod read()¶: Returns an MLReader instance for this class.

save(path)¶: Save this ML instance to the given path, a shortcut of ‘write().save(path)’.

set(param, value)¶: Sets a parameter in the embedded param map.

setBinary(value)[source]¶: Sets the value of binary.

New in version 2.0.0.

setInputCol(value)[source]¶: Sets the value of inputCol.

setMaxDF(value)[source]¶: Sets the value of maxDF.

New in version 2.4.0.

setMinDF(value)[source]¶: Sets the value of minDF.

New in version 1.6.0.

setMinTF(value)[source]¶: Sets the value of minTF.

New in version 1.6.0.

setOutputCol(value)[source]¶: Sets the value of outputCol.

setParams(self, \*, minTF=1.0, minDF=1.0, maxDF=2 ** 63 - 1, vocabSize=1 << 18, binary=False, inputCol=None, outputCol=None)[source]¶: Set the params for the CountVectorizer

New in version 1.6.0.

setVocabSize(value)[source]¶: Sets the value of vocabSize.

New in version 1.6.0.

write()¶: Returns an MLWriter instance for this ML instance.

Attributes Documentation

binary = Param(parent='undefined', name='binary', doc='Binary toggle to control the output vector values. If True, all nonzero counts (after minTF filter applied) are set to 1. This is useful for discrete probabilistic models that model binary events rather than integer counts. Default False')¶

inputCol = Param(parent='undefined', name='inputCol', doc='input column name.')¶

maxDF = Param(parent='undefined', name='maxDF', doc='Specifies the maximum number of different documents a term could appear in to be included in the vocabulary. A term that appears more than the threshold will be ignored. If this is an integer >= 1, this specifies the maximum number of documents the term could appear in; if this is a double in [0,1), then this specifies the maximum fraction of documents the term could appear in. Default (2^63) - 1')¶

minDF = Param(parent='undefined', name='minDF', doc='Specifies the minimum number of different documents a term must appear in to be included in the vocabulary. If this is an integer >= 1, this specifies the number of documents the term must appear in; if this is a double in [0,1), then this specifies the fraction of documents. Default 1.0')¶

minTF = Param(parent='undefined', name='minTF', doc="Filter to ignore rare words in a document. For each document, terms with frequency/count less than the given threshold are ignored. If this is an integer >= 1, then this specifies a count (of times the term must appear in the document); if this is a double in [0,1), then this specifies a fraction (out of the document's token count). Note that the parameter is only used in transform of CountVectorizerModel and does not affect fitting. Default 1.0")¶

outputCol = Param(parent='undefined', name='outputCol', doc='output column name.')¶

params¶: Returns all params ordered by name. The default implementation uses dir() to get all attributes of type Param.

vocabSize = Param(parent='undefined', name='vocabSize', doc='max size of the vocabulary. Default 1 << 18.')¶

ChiSqSelectorModel CountVectorizerModel