python - 选择 pandas DataFrame 中第一行的值

Question

我有以下数据框

                  AAPL         F       IBM
    Date            
    2016-05-02  46.536664   13.62   143.881476
    2016-05-03  47.302004   13.43   142.752373
    2016-05-04  46.810001   13.31   142.871221
    2016-05-05  46.619999   13.32   145.070003
    2016-05-06  46.360000   13.44   147.289993

我想将每一列除以第一行的值，然后乘以 100。计算后，前 2 行应如下所示:

                AAPL          F        IBM
    Date
    2016-05-02  100          100       100
    2016-05-03  101.63       98.60     99.21

我很挣扎，但我无法得到它。任何帮助表示赞赏

Answer 1

尝试这样的事情:

df /= df.iloc[0]/100

或

df = df.apply(lambda x: x/x.iloc[0]*100)

测试:

In [51]: df
Out[51]:
                 AAPL      F         IBM
Date
2016-05-02  46.536664  13.62  143.881476
2016-05-03  47.302004  13.43  142.752373
2016-05-04  46.810001  13.31  142.871221
2016-05-05  46.619999  13.32  145.070003
2016-05-06  46.360000  13.44  147.289993

输出:

In [63]: df /= df.iloc[0]/100

In [64]: df
Out[64]:
                  AAPL           F         IBM
Date
2016-05-02  100.000000  100.000000  100.000000
2016-05-03  101.644596   98.604993   99.215255
2016-05-04  100.587358   97.723935   99.297856
2016-05-05  100.179074   97.797357  100.826046
2016-05-06   99.620377   98.678414  102.368976