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Diffstat (limited to 'python/pyspark/ml/feature.py')
-rw-r--r-- | python/pyspark/ml/feature.py | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/python/pyspark/ml/feature.py b/python/pyspark/ml/feature.py new file mode 100644 index 0000000000..e088acd0ca --- /dev/null +++ b/python/pyspark/ml/feature.py @@ -0,0 +1,82 @@ +# +# Licensed to the Apache Software Foundation (ASF) under one or more +# contributor license agreements. See the NOTICE file distributed with +# this work for additional information regarding copyright ownership. +# The ASF licenses this file to You under the Apache License, Version 2.0 +# (the "License"); you may not use this file except in compliance with +# the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. +# + +from pyspark.ml.param.shared import HasInputCol, HasOutputCol, HasNumFeatures +from pyspark.ml.util import inherit_doc +from pyspark.ml.wrapper import JavaTransformer + +__all__ = ['Tokenizer', 'HashingTF'] + + +@inherit_doc +class Tokenizer(JavaTransformer, HasInputCol, HasOutputCol): + """ + A tokenizer that converts the input string to lowercase and then + splits it by white spaces. + + >>> from pyspark.sql import Row + >>> dataset = sqlCtx.inferSchema(sc.parallelize([Row(text="a b c")])) + >>> tokenizer = Tokenizer() \ + .setInputCol("text") \ + .setOutputCol("words") + >>> print tokenizer.transform(dataset).head() + Row(text=u'a b c', words=[u'a', u'b', u'c']) + >>> print tokenizer.transform(dataset, {tokenizer.outputCol: "tokens"}).head() + Row(text=u'a b c', tokens=[u'a', u'b', u'c']) + """ + + _java_class = "org.apache.spark.ml.feature.Tokenizer" + + +@inherit_doc +class HashingTF(JavaTransformer, HasInputCol, HasOutputCol, HasNumFeatures): + """ + Maps a sequence of terms to their term frequencies using the + hashing trick. + + >>> from pyspark.sql import Row + >>> dataset = sqlCtx.inferSchema(sc.parallelize([Row(words=["a", "b", "c"])])) + >>> hashingTF = HashingTF() \ + .setNumFeatures(10) \ + .setInputCol("words") \ + .setOutputCol("features") + >>> print hashingTF.transform(dataset).head().features + (10,[7,8,9],[1.0,1.0,1.0]) + >>> params = {hashingTF.numFeatures: 5, hashingTF.outputCol: "vector"} + >>> print hashingTF.transform(dataset, params).head().vector + (5,[2,3,4],[1.0,1.0,1.0]) + """ + + _java_class = "org.apache.spark.ml.feature.HashingTF" + + +if __name__ == "__main__": + import doctest + from pyspark.context import SparkContext + from pyspark.sql import SQLContext + globs = globals().copy() + # The small batch size here ensures that we see multiple batches, + # even in these small test examples: + sc = SparkContext("local[2]", "ml.feature tests") + sqlCtx = SQLContext(sc) + globs['sc'] = sc + globs['sqlCtx'] = sqlCtx + (failure_count, test_count) = doctest.testmod( + globs=globs, optionflags=doctest.ELLIPSIS) + sc.stop() + if failure_count: + exit(-1) |