Summarizer

class pyspark.ml.stat.Summarizer[source]

Tools for vectorized statistics on MLlib Vectors. The methods in this package provide various statistics for Vectors contained inside DataFrames. This class lets users pick the statistics they would like to extract for a given column.

New in version 2.4.0.

Examples

>>> from pyspark.ml.stat import Summarizer
>>> from pyspark.sql import Row
>>> from pyspark.ml.linalg import Vectors
>>> summarizer = Summarizer.metrics("mean", "count")
>>> df = sc.parallelize([Row(weight=1.0, features=Vectors.dense(1.0, 1.0, 1.0)),
...                      Row(weight=0.0, features=Vectors.dense(1.0, 2.0, 3.0))]).toDF()
>>> df.select(summarizer.summary(df.features, df.weight)).show(truncate=False)
+-----------------------------------+
|aggregate_metrics(features, weight)|
+-----------------------------------+
|{[1.0,1.0,1.0], 1}                 |
+-----------------------------------+

>>> df.select(summarizer.summary(df.features)).show(truncate=False)
+--------------------------------+
|aggregate_metrics(features, 1.0)|
+--------------------------------+
|{[1.0,1.5,2.0], 2}              |
+--------------------------------+

>>> df.select(Summarizer.mean(df.features, df.weight)).show(truncate=False)
+--------------+
|mean(features)|
+--------------+
|[1.0,1.0,1.0] |
+--------------+

>>> df.select(Summarizer.mean(df.features)).show(truncate=False)
+--------------+
|mean(features)|
+--------------+
|[1.0,1.5,2.0] |
+--------------+

Methods

count(col[, weightCol])

return a column of count summary

max(col[, weightCol])

return a column of max summary

mean(col[, weightCol])

return a column of mean summary

metrics(*metrics)

Given a list of metrics, provides a builder that it turns computes metrics from a column.

min(col[, weightCol])

return a column of min summary

normL1(col[, weightCol])

return a column of normL1 summary

normL2(col[, weightCol])

return a column of normL2 summary

numNonZeros(col[, weightCol])

return a column of numNonZero summary

std(col[, weightCol])

return a column of std summary

sum(col[, weightCol])

return a column of sum summary

variance(col[, weightCol])

return a column of variance summary

Methods Documentation

static count(col, weightCol=None)[source]

return a column of count summary

New in version 2.4.0.

static max(col, weightCol=None)[source]

return a column of max summary

New in version 2.4.0.

static mean(col, weightCol=None)[source]

return a column of mean summary

New in version 2.4.0.

static metrics(*metrics)[source]

Given a list of metrics, provides a builder that it turns computes metrics from a column.

See the documentation of Summarizer for an example.

The following metrics are accepted (case sensitive):
  • mean: a vector that contains the coefficient-wise mean.

  • sum: a vector that contains the coefficient-wise sum.

  • variance: a vector tha contains the coefficient-wise variance.

  • std: a vector tha contains the coefficient-wise standard deviation.

  • count: the count of all vectors seen.

  • numNonzeros: a vector with the number of non-zeros for each coefficients

  • max: the maximum for each coefficient.

  • min: the minimum for each coefficient.

  • normL2: the Euclidean norm for each coefficient.

  • normL1: the L1 norm of each coefficient (sum of the absolute values).

New in version 2.4.0.

Returns
pyspark.ml.stat.SummaryBuilder

Notes

Currently, the performance of this interface is about 2x~3x slower than using the RDD interface.

Examples

metricsstr

metrics that can be provided.

static min(col, weightCol=None)[source]

return a column of min summary

New in version 2.4.0.

static normL1(col, weightCol=None)[source]

return a column of normL1 summary

New in version 2.4.0.

static normL2(col, weightCol=None)[source]

return a column of normL2 summary

New in version 2.4.0.

static numNonZeros(col, weightCol=None)[source]

return a column of numNonZero summary

New in version 2.4.0.

static std(col, weightCol=None)[source]

return a column of std summary

New in version 3.0.0.

static sum(col, weightCol=None)[source]

return a column of sum summary

New in version 3.0.0.

static variance(col, weightCol=None)[source]

return a column of variance summary

New in version 2.4.0.