1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
|
#
# 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.rdd import ignore_unicode_prefix
from pyspark.ml.param.shared import HasInputCol, HasInputCols, HasOutputCol, HasNumFeatures
from pyspark.ml.util import keyword_only
from pyspark.ml.wrapper import JavaTransformer
from pyspark.mllib.common import inherit_doc
__all__ = ['Tokenizer', 'HashingTF', 'VectorAssembler']
@inherit_doc
@ignore_unicode_prefix
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
>>> df = sc.parallelize([Row(text="a b c")]).toDF()
>>> tokenizer = Tokenizer(inputCol="text", outputCol="words")
>>> tokenizer.transform(df).head()
Row(text=u'a b c', words=[u'a', u'b', u'c'])
>>> # Change a parameter.
>>> tokenizer.setParams(outputCol="tokens").transform(df).head()
Row(text=u'a b c', tokens=[u'a', u'b', u'c'])
>>> # Temporarily modify a parameter.
>>> tokenizer.transform(df, {tokenizer.outputCol: "words"}).head()
Row(text=u'a b c', words=[u'a', u'b', u'c'])
>>> tokenizer.transform(df).head()
Row(text=u'a b c', tokens=[u'a', u'b', u'c'])
>>> # Must use keyword arguments to specify params.
>>> tokenizer.setParams("text")
Traceback (most recent call last):
...
TypeError: Method setParams forces keyword arguments.
"""
_java_class = "org.apache.spark.ml.feature.Tokenizer"
@keyword_only
def __init__(self, inputCol=None, outputCol=None):
"""
__init__(self, inputCol=None, outputCol=None)
"""
super(Tokenizer, self).__init__()
kwargs = self.__init__._input_kwargs
self.setParams(**kwargs)
@keyword_only
def setParams(self, inputCol=None, outputCol=None):
"""
setParams(self, inputCol="input", outputCol="output")
Sets params for this Tokenizer.
"""
kwargs = self.setParams._input_kwargs
return self._set(**kwargs)
@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
>>> df = sc.parallelize([Row(words=["a", "b", "c"])]).toDF()
>>> hashingTF = HashingTF(numFeatures=10, inputCol="words", outputCol="features")
>>> hashingTF.transform(df).head().features
SparseVector(10, {7: 1.0, 8: 1.0, 9: 1.0})
>>> hashingTF.setParams(outputCol="freqs").transform(df).head().freqs
SparseVector(10, {7: 1.0, 8: 1.0, 9: 1.0})
>>> params = {hashingTF.numFeatures: 5, hashingTF.outputCol: "vector"}
>>> hashingTF.transform(df, params).head().vector
SparseVector(5, {2: 1.0, 3: 1.0, 4: 1.0})
"""
_java_class = "org.apache.spark.ml.feature.HashingTF"
@keyword_only
def __init__(self, numFeatures=1 << 18, inputCol=None, outputCol=None):
"""
__init__(self, numFeatures=1 << 18, inputCol=None, outputCol=None)
"""
super(HashingTF, self).__init__()
self._setDefault(numFeatures=1 << 18)
kwargs = self.__init__._input_kwargs
self.setParams(**kwargs)
@keyword_only
def setParams(self, numFeatures=1 << 18, inputCol=None, outputCol=None):
"""
setParams(self, numFeatures=1 << 18, inputCol=None, outputCol=None)
Sets params for this HashingTF.
"""
kwargs = self.setParams._input_kwargs
return self._set(**kwargs)
@inherit_doc
class VectorAssembler(JavaTransformer, HasInputCols, HasOutputCol):
"""
A feature transformer that merges multiple columns into a vector column.
>>> from pyspark.sql import Row
>>> df = sc.parallelize([Row(a=1, b=0, c=3)]).toDF()
>>> vecAssembler = VectorAssembler(inputCols=["a", "b", "c"], outputCol="features")
>>> vecAssembler.transform(df).head().features
DenseVector([1.0, 0.0, 3.0])
>>> vecAssembler.setParams(outputCol="freqs").transform(df).head().freqs
DenseVector([1.0, 0.0, 3.0])
>>> params = {vecAssembler.inputCols: ["b", "a"], vecAssembler.outputCol: "vector"}
>>> vecAssembler.transform(df, params).head().vector
DenseVector([0.0, 1.0])
"""
_java_class = "org.apache.spark.ml.feature.VectorAssembler"
@keyword_only
def __init__(self, inputCols=None, outputCol=None):
"""
__init__(self, inputCols=None, outputCol=None)
"""
super(VectorAssembler, self).__init__()
self._setDefault()
kwargs = self.__init__._input_kwargs
self.setParams(**kwargs)
@keyword_only
def setParams(self, inputCols=None, outputCol=None):
"""
setParams(self, inputCols=None, outputCol=None)
Sets params for this VectorAssembler.
"""
kwargs = self.setParams._input_kwargs
return self._set(**kwargs)
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")
sqlContext = SQLContext(sc)
globs['sc'] = sc
globs['sqlContext'] = sqlContext
(failure_count, test_count) = doctest.testmod(
globs=globs, optionflags=doctest.ELLIPSIS)
sc.stop()
if failure_count:
exit(-1)
|
