August 2015
Intermediate to advanced
312 pages
7h 28m
Japanese
Content preview from 初めてのSpark
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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.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.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.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.
15
2.3 Spark の中核となっている概念
2.3
Spark
のなている
初めての
Spark
のコードをシェルを使って実行できたところで、さらに詳しく
Spark
のプログ
ラミングについて学んでいきましょう。
高いレベルから見れば、すべての
Spark
のアプリケーションには、クラスタ上で複数の並列操
作を起動するムが含まれます。このドライバプログラムは、アプリケーションの
main
関数を持ち、クラスタ上の分散データセットを定義してから、それらに対して操作を適用し
ていきます。先ほどの例では、ドライバプログラムは
Spark
シェルそのものであり、読者のみな
さんは実行したい操作を入力するだけでした。
ドライバプログラムは、
SparkContext
オブジェクトを通じて
Spark
にアクセスします。
Spark
Context
は、演算クラスタへの接続を表現します。シェルの中では、
SparkContext
は
sc
という変
数として自動的に生成されます。
2-3
のように
sc
を出力して、その型を見てみてください。
2-3
sc
>>> sc
<pyspark.context.SparkContext object at 0x1025b8f90>
SparkContext
があれば、それを使って
RDD
を構築できます。
2-1
や
2-2
では、
sc.textFile()
を呼んで、ファイル中のテキストの行を表す
RDD
を生成しました。その後は、
count()
などの操作をこれらの行に対して実行できます。 ...
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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.