May 2018
Intermediate to advanced
228 pages
4h 11m
Japanese
Content preview from Rによるテキストマイニング ―tidytextを活用したデータ分析と可視化の基礎
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■
181
9
章
ケーススタディ：
Usenet
テキストの分析
最後の
9
章では、
1993
年に
Usenet
の
20
のニュ ースグル ー プに送ら れた
20,000
通のメッセージの分析を最初から最後まで紹介しましょう。このデータセットの
Usenet
には、政治、宗教、自動車、スポーツ、暗号学などのテーマを扱うニュース
グループが含まれており、多くのユーザが書いた内容の豊かなテキストセットを提
供しています。このデータセットは、
http://qwone.com/~jason/20Newsgroups/
で
20news-bydate.tar.gz
ファイルとして公開されており、テキスト分析と機械学習の練
習用に広く使われています。
9.1
前処理
まず、
20news-bydate
からすべてのメッセージを読み出します。
20news-bydate
フォ
ルダには、
1
つのメッセージを
1
つのファイルとして格納する複数のサブフォルダが
含まれ
ています。この種のファイルは、
read_lines()
、
map()
、
unnest()
を組み合
わせて読み出すことができます。
文書全体を読み出すこのステップは、数分かかることがあります。
library(dplyr)
library(tidyr)
library(purrr)
library(readr)
training_folder <- "data/20news-bydate/20news-bydate-train/"
182
■
9
章 ケーススタディ：
Usenet
テキストの分析
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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.