July 2018
Intermediate to advanced
596 pages
13h 35m
Japanese
Content preview from Pythonによるデータ分析入門 第2版 ―NumPy、pandasを使ったデータ処理
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324
10
章 データの集約とグループ演算
6 -0.713544 -0.831154 -2.370232 -1.860761 -0.860757
配列、ディクショナリ、シリーズと関数が混在していても、すべてが内部的に配列に変換されるので
問題ありません。
In [45]: key_list = ['one', 'one', 'one', 'two', 'two']
In [46]: people.groupby([len, key_list]).min()
Out[46]:
a b c d e
3 one -0.539741 -1.296221 0.274992 -1.021228 -0.577087
two 0.124121 0.302614 0.523772 0.000940 1.343810
5 one 0.886429 -2.001
637 -0.371843 1.669025 -0.438570
6 two -0.713544 -0.831154 -2.370232 -1.860761 -0.860757
10.1.5
インデックス階層によるグループ化
階層を持つインデックスを使う際に決定的に便利なのは、軸のインデックスの階層を使って集約がで
きる機能です。
1
つ例を見てみましょう。
In [47]: columns = pd.MultiIndex.from_arrays([['US', 'US', 'US', 'JP', 'JP'],
....: [1, 3, 5, 1, 3]],
....: ...
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