Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
708 views
in Technique[技术] by (71.8m points)

python - Fit a dataframe into randomForest pyspark

I have a DataFrame that looks like this:

+--------------------+------------------+
|            features|           labels |
+--------------------+------------------+
|[-0.38475, 0.568...]|          label1  |
|[0.645734, 0.699...]|          label2  |
|     .....          |          ...     |
+--------------------+------------------+

Both columns are of String type (StringType()), I would like to fit this into spark ml randomForest. To do so, I need to convert the features columns into a vector containing floats. Does any one have any idea How to do so ?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

If you are using Spark 2.x, I believe that this is what you need :

from pyspark.sql.functions import udf
from pyspark.mllib.linalg import Vectors
from pyspark.ml.linalg import VectorUDT
from pyspark.ml.feature import StringIndexer

df = spark.createDataFrame([("[-0.38475, 0.568]", "label1"), ("[0.645734, 0.699]", "label2")], ("features", "label"))

def parse(s):
  try:
    return Vectors.parse(s).asML()
  except:
    return None

parse_ = udf(parse, VectorUDT())

parsed = df.withColumn("features", parse_("features"))

indexer = StringIndexer(inputCol="label", outputCol="label_indexed")

indexer.fit(parsed).transform(parsed).show()
## +----------------+------+-------------+
## |        features| label|label_indexed|
## +----------------+------+-------------+
## |[-0.38475,0.568]|label1|          0.0|
## |[0.645734,0.699]|label2|          1.0|
## +----------------+------+-------------+

With Spark 1.6, it isn't much different :

from pyspark.sql.functions import udf
from pyspark.ml.feature import StringIndexer
from pyspark.mllib.linalg import Vectors, VectorUDT

df = sqlContext.createDataFrame([("[-0.38475, 0.568]", "label1"), ("[0.645734, 0.699]", "label2")], ("features", "label"))

parse_ = udf(Vectors.parse, VectorUDT())

parsed = df.withColumn("features", parse_("features"))

indexer = StringIndexer(inputCol="label", outputCol="label_indexed")

indexer.fit(parsed).transform(parsed).show()
## +----------------+------+-------------+
## |        features| label|label_indexed|
## +----------------+------+-------------+
## |[-0.38475,0.568]|label1|          0.0|
## |[0.645734,0.699]|label2|          1.0|
## +----------------+------+-------------+

Vectors has a parse function that can help you achieve what you are trying to do.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...