August 2017
Intermediate to advanced
500 pages
12h 3m
Japanese
Content preview from PythonとJavaScriptではじめるデータビジュアライゼーション
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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.
188
8 章 pandas 入門
import sqlalchemy
engine = sqlalchemy.create_engine(
'mysql://USER:PASSWORD@localhost/db') #
❶
df = pd.read_sql('nobel_winners', engine) #
❷
❶ ここでは
MySQL
データベースを使用する。
SQLAlchemy
は一般的に使用するすべてのデータベー
ス用のエンジンを作成できる。
❷
SQL
テーブル
'nobel_winners'
の内容を
DataFrame
に読み込む。
read_sql
は
read_sql_table
と
read_sql_query
メソッドの便利なラッパーです。最初の引数に
適した処理を行います。
DataFrame
は簡単に
SQL
データベースへ書き込むことができます。先ほど作成したエンジンを
使います。
# DataFrame df
を
SQL
テーブル
nobel_winners
に保存する
df.to_sql('nobel_winners', engine)
パケットサイズ制限によるエラーが生じる場合には、
chunksize
パラメータで一度に書き込む行
数を設定します。
#
一度に
500
行を書き込む
df.to_sql('nobel_winners', engine, chunksize=500)
pandas
は適切に処理し、オブジェクトのデータ型を推測してデータを適切な
SQL
型に対応させ
ようとします。必要に応じて、読み込み呼び出しでデフォルトの型をオーバーライドできます。 ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
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.