sparknlp.annotator.PerceptronApproach

class sparknlp.annotator.PerceptronApproach[source]

Bases: sparknlp.common.AnnotatorApproach

Trains an averaged Perceptron model to tag words part-of-speech. Sets a POS tag to each word within a sentence.

For pretrained models please see the PerceptronModel.

The training data needs to be in a Spark DataFrame, where the column needs to consist of Annotations of type POS. The Annotation needs to have member result set to the POS tag and have a "word" mapping to its word inside of member metadata. This DataFrame for training can easily created by the helper class POS.

>>> POS().readDataset(spark, datasetPath) \
...     .selectExpr("explode(tags) as tags").show(truncate=False)
+---------------------------------------------+
|tags                                         |
+---------------------------------------------+
|[pos, 0, 5, NNP, [word -> Pierre], []]       |
|[pos, 7, 12, NNP, [word -> Vinken], []]      |
|[pos, 14, 14, ,, [word -> ,], []]            |
|[pos, 31, 34, MD, [word -> will], []]        |
|[pos, 36, 39, VB, [word -> join], []]        |
|[pos, 41, 43, DT, [word -> the], []]         |
|[pos, 45, 49, NN, [word -> board], []]       |
                        ...

For extended examples of usage, see the Spark NLP Workshop.

Input Annotation types

Output Annotation type

TOKEN, DOCUMENT

POS

Parameters
posCol

Column name for Array of POS tags that match tokens

nIterations

Number of iterations in training, converges to better accuracy, by default 5

Examples

>>> import sparknlp
>>> from sparknlp.base import *
>>> from sparknlp.annotator import *
>>> from sparknlp.training import *
>>> from pyspark.ml import Pipeline
>>> documentAssembler = DocumentAssembler() \
...     .setInputCol("text") \
...     .setOutputCol("document")
>>> sentence = SentenceDetector() \
...     .setInputCols(["document"]) \
...     .setOutputCol("sentence")
>>> tokenizer = Tokenizer() \
...     .setInputCols(["sentence"]) \
...     .setOutputCol("token")
>>> datasetPath = "src/test/resources/anc-pos-corpus-small/test-training.txt"
>>> trainingPerceptronDF = POS().readDataset(spark, datasetPath)
>>> trainedPos = PerceptronApproach() \
...     .setInputCols(["document", "token"]) \
...     .setOutputCol("pos") \
...     .setPosColumn("tags") \
...     .fit(trainingPerceptronDF)
>>> pipeline = Pipeline().setStages([
...     documentAssembler,
...     sentence,
...     tokenizer,
...     trainedPos
... ])
>>> data = spark.createDataFrame([["To be or not to be, is this the question?"]]).toDF("text")
>>> result = pipeline.fit(data).transform(data)
>>> result.selectExpr("pos.result").show(truncate=False)
+--------------------------------------------------+
|result                                            |
+--------------------------------------------------+
|[NNP, NNP, CD, JJ, NNP, NNP, ,, MD, VB, DT, CD, .]|
+--------------------------------------------------+

Methods

__init__()

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.

getInputCols()

Gets current column names of input annotations.

getLazyAnnotator()

Gets whether Annotator should be evaluated lazily in a RecursivePipeline.

getNIterations()

Gets number of iterations in training, by default 5.

getOrDefault(param)

Gets the value of a param in the user-supplied param map or its default value.

getOutputCol()

Gets output column name of annotations.

getParam(paramName)

Gets a param by its name.

getParamValue(paramName)

Gets the value of a parameter.

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.

setInputCols(*value)

Sets column names of input annotations.

setIterations(value)

Sets number of iterations in training, by default 5.

setLazyAnnotator(value)

Sets whether Annotator should be evaluated lazily in a RecursivePipeline.

setOutputCol(value)

Sets output column name of annotations.

setParamValue(paramName)

Sets the value of a parameter.

setPosColumn(value)

Sets column name for Array of POS tags that match tokens.

write()

Returns an MLWriter instance for this ML instance.

Attributes

getter_attrs

inputCols

lazyAnnotator

nIterations

outputCol

params

Returns all params ordered by name.

posCol

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

extra – Extra parameters to copy to the new instance

Returns

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

extra – extra param values

Returns

merged param map

fit(dataset, params=None)

Fits a model to the input dataset with optional parameters.

Parameters
  • dataset – input dataset, which is an instance of pyspark.sql.DataFrame

  • params – 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

fitted model(s)

New in version 1.3.0.

fitMultiple(dataset, paramMaps)

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

Parameters
  • dataset – input dataset, which is an instance of pyspark.sql.DataFrame.

  • paramMaps – A Sequence of param maps.

Returns

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.

New in version 2.3.0.

getInputCols()

Gets current column names of input annotations.

getLazyAnnotator()

Gets whether Annotator should be evaluated lazily in a RecursivePipeline.

getNIterations()[source]

Gets number of iterations in training, by default 5.

Returns
int

Number of iterations in training

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 output column name of annotations.

getParam(paramName)

Gets a param by its name.

getParamValue(paramName)

Gets the value of a parameter.

Parameters
paramNamestr

Name of the parameter

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).

property params

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

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.

setInputCols(*value)

Sets column names of input annotations.

Parameters
*valuestr

Input columns for the annotator

setIterations(value)[source]

Sets number of iterations in training, by default 5.

Parameters
valueint

Number of iterations in training

setLazyAnnotator(value)

Sets whether Annotator should be evaluated lazily in a RecursivePipeline.

Parameters
valuebool

Whether Annotator should be evaluated lazily in a RecursivePipeline

setOutputCol(value)

Sets output column name of annotations.

Parameters
valuestr

Name of output column

setParamValue(paramName)

Sets the value of a parameter.

Parameters
paramNamestr

Name of the parameter

setPosColumn(value)[source]

Sets column name for Array of POS tags that match tokens.

Parameters
valuestr

Name of column for Array of POS tags

uid

A unique id for the object.

write()

Returns an MLWriter instance for this ML instance.