November 2017
Intermediate to advanced
328 pages
6h 51m
Japanese
Content preview from 入門 PySpark ―PythonとJupyterで活用するSpark 2エコシステム
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104
6
章
ML
パッケージ
は
'features'
列を生成します。最後にこのステージからの出力が
logistic
オブジェクトに渡され、
logistic
オブジェクトが最終的なモデルの推定を行います。
.fit(...)
メソッドが 返す
PipelineModel
オ ブ ジ ェ ク ト（ 上 の コ ー ド で の
model
オ ブ ジ ェ クト ）を
使えば予測ができます。それには、先ほど作成したテスト用のデータセットを渡して
.transform(...)
メソッドを呼びます 。次のコマンドで 、
test_model
の様子を見ることができます。
test_model.take(1)
結果は次のようになります。
ここからわかるとおり、
Transfomers
と
Estimators
のすべての列が得られています。ロジス
ティック回帰のモデルから出力されている列もあります。
rawPrediction
は特徴の線形結合と回帰
係数のβの値、
probability
はクラスごとに計算された確率、そして
prediction
は最終的なクラ
スの判定結果です。
6.2.6
モデルのパフォーマンス評価
ここでモデルの動作結果を検証しなければならないことは言うまでもありません。PySparkのML
パッケージの
.evaluation
セクションには、クラシフィケーションや回帰のための評価メソッドが数
多く用意されています。
import pyspark.ml.evaluation as ev
ここでは
BinaryClassficationEvaluator ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.