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.
178
9 章 Spark SQL
9-20
Python
Parquet
pandaFriends.saveAsParquetFile("hdfs://...")
9.3.3
JSON
同じスキーマに適合するレコード群を含む
JSON
ファイルがある場合、
Spark SQL
はそのファ
イルを走査してスキーマを推測し、フィールドを名前でアクセスできるようにしてくれます（
9-21
）。
JSON
のレコードを大量に含むディレクトリを扱ったことがあるなら、
Spark SQL
のス
キーマ推測によって、特別なロード用のコードを書くことなく、効率的にデータの処理を始めるこ
とができます。
9-22
から
9-24
に示す通り、
JSON
のデータは
hiveCtx
の
jsonFile()
関数を
呼ぶだけでロードできます。データから推定されたスキーマを知りたい場合は、生成された
SchemaRDD
の
printSchema
を呼びます（
9-25
）。
9-21
ー
{"name": "Holden"}
{"name":"Sparky The Bear", "lovesPandas":true, "knows":{"friends": ["holden"]}}
9-22
Spark SQL
Python
JSON
ー
input = hiveCtx.jsonFile(inputFile)
9-23
Spark SQL
Scala
JSON
ー
val input ...
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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.