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
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185
8.5 DataFrame の作成と保存
ジェクトが
pandas
のパーサで
JSON
に変換できない場合に呼び出す
default_handler
などのパラ
メータもあります。詳細は
pandas
ドキュメント（
http://pandas.pydata.org/pandas-docs/dev/
io.html#writing-json
）を参照してください。
8.5.2
CSV
pandas
のデータテーブルの精神にふさわしく、
pandas
の
CSV
ファイル処理は高度で、考えら
れるほぼすべてのデータに対応できます。一般的な
CSV
ファイルは、パラメータなしで読み込み
ます。
# data.csv:
# name,category
# "Albert Einstein",Physics
# "Marie Curie",Chemistry
df = pd.read_csv('data.csv')
df
Out:
name category
0 Albert Einstein Physics
1 Marie Curie Chemistry
しかし、世の中には多くの
CSV
型データがあり、カンマ区切りでないものや、空白や特殊文字
を含む文字列に特殊な引用符を使うものがあります。その場合には、読み込み時に別要素を指定で
きます。
Python
の便利な
StringIO
モジュール
†
を使ってファイルからの読み込みをエミュレート
します
‡
。
from StringIO import StringIO
§
data = " `Albert Einstein`| ...
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