python - 在 pandas 列上应用函数

Question

我创建了下面的函数，它根据两个输入向量返回一个向量。我有一个具有不同列的 pandas 数据框，我想将该函数应用于我的数据框的某些列(一个 pandas 列将是我的函数的第一个向量(名义)，另一个是我的函数的第二个向量(CPI)和我会将函数的结果分配给新的 pandas 列)。我怎样才能做到呢？

非常感谢您的帮助，

皮埃尔

nominal=[10,10,10,10,10,10,10,10,10,10,10,10]
CPI=[0.02,0.02,0.02,0.02,0.02,0.02,0.02,0.02,0.02,0.02,0.02,0.02]

def nominal_to_real(nominal,CPI):
    real=[]
    product=1
    for i in range(len(nominal)):
        product*=(CPI[i]+1)**(1/12)     
        real.append(nominal[i]/product)
    return real

Answer 1

您可以使用cumprod对于矢量化解决方案:

nominal=[10,10,10,10,10,10,10,10,10,10,10,10]
CPI=[0.02,0.02,0.02,0.02,0.02,0.02,0.02,0.02,0.02,0.02,0.02,0.02]

def nominal_to_real(nominal,CPI):
    real=[]
    product=1
    for i in range(len(nominal)):
        product*=(CPI[i]+1)**(1/12)     
        real.append(nominal[i]/product)
    return real

a = nominal_to_real(nominal,CPI)
df = pd.DataFrame(np.c_[nominal, CPI, a], columns=['nominal','CPI','real'])

<小时/>

df['real1'] = df['nominal'] / ((df['CPI'] + 1)**(1/12)).cumprod() 
print (df)
    nominal   CPI      real     real1
0      10.0  0.02  9.983511  9.983511
1      10.0  0.02  9.967050  9.967050
2      10.0  0.02  9.950616  9.950616
3      10.0  0.02  9.934209  9.934209
4      10.0  0.02  9.917829  9.917829
5      10.0  0.02  9.901475  9.901475
6      10.0  0.02  9.885149  9.885149
7      10.0  0.02  9.868850  9.868850
8      10.0  0.02  9.852578  9.852578
9      10.0  0.02  9.836332  9.836332
10     10.0  0.02  9.820114  9.820114
11     10.0  0.02  9.803922  9.803922