pandas 按第一行划分数据帧
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Divide DataFrame by first row
提问by bigsleep
I have checked the documentation. I don't understand the way to index a Pandas DataFrame.
我已经检查了文档。我不明白索引 Pandas DataFrame 的方法。
I would like to divide a DataFrame of stock prices by their respective initial values to index the different stocks to 100. I want to compare their performance. The DataFrame looks like this:
我想将股票价格的 DataFrame 除以它们各自的初始值，以将不同的股票索引为 100。我想比较它们的表现。数据框看起来像这样：
>>> IndexPrices
<class 'pandas.core.frame.DataFrame'>
DatetimeIndex: 157 entries, 1999-12-31 00:00:00 to 2012-12-31 00:00:00
Freq: M
Data columns:
MSCI WORLD :G U$ 148 non-null values
S&P 500 COMPOSITE 148 non-null values
DAX 30 PERFORMANCE 148 non-null values
RUSSELL 2000 148 non-null values
FTSE 100 148 non-null values
US Treasury Bond Yields 30 Year Bond 148 non-null values
dtypes: float64(6)
I have stuff like this, but it's not getting me anywhere.
我有这样的东西，但它没有让我去任何地方。
IndexPrices.divide(IndexPrices[0:1])
回答by Wouter Overmeire
In [193]: df
Out[193]:
A B C D
a 1 8 9 1
b 5 4 3 6
c 4 6 1 3
d 1 0 2 9
In [194]: df.divide(df.ix[0] / 100)
Out[194]:
A B C D
a 100 100 100.000000 100
b 500 50 33.333333 600
c 400 75 11.111111 300
d 100 0 22.222222 900
