October 2014
Intermediate to advanced
288 pages
6h 27m
Japanese
Content preview from 実践 機械学習システム
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90
5
章 クラス分類：悪い回答を判別する
array([[ 0.5, 0.5]])
5.4.2
特徴量について模索する
それでは、どのような特徴量を分類器に入力すれば良いでしょうか？ どのような特徴量が最も識別
性をもつでしょうか？
meta
というディクショナリ型の変数には、
TimeToAnswer
という属性が既に存在しますが、それ
だけではあまり有効に用いることはできないでしょう。それから
Text
という属性はHTML形式のテキ
ストデータであるため、そのまま分類器に入力することはできません。くり返しになりますが、分類器
に入力できるのは数値だけです。そのため、テキストデータから特徴量を抽出する必要があります。
一つの仮説として考えられるのは、文書中により多くのURLリンクが存在すればするほど、良い回
答である可能性が高くなるというものです。文書の質を計測する指標として、テキストデータ中に存在
する「リンクの数」を用いることができるかもしれません
。ここでは、回答に対してソースコード中に
含まれるリンク
―
具体例としてソースコードを記載することもあるでしょう
―
は除外して、通常の
文章中に含まれるリンクだけをカウントすることにします（それが望まれることだと思います）。
import re
#
正規表現を用いて「ソースコード」と「
URL
リンク」を見つける
code_match = re.compile('<pre>(.*?)</pre>',
re.MULTILINE|re.DOTALL)
link_match = re.compile('<a ...
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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.