如何在Python中返回意甲？

Question

我有名为‘hasta_2019’的数据：

infl_gen    alim_proc   alim_fres   bienes  ener serv
fecha                       
2001-01 71.94   63.25   68.91   87.30   59.91   69.34
2001-02 71.94   63.36   68.60   87.18   60.21   69.45
2001-03 72.52   63.43   69.43   88.64   60.15   69.70
2001-04 73.17   63.49   69.65   90.06   61.12   70.10
2001-05 73.43   63.81   69.99   90.35   62.21   70.06
2001-06 73.63   63.95   70.16   90.26   62.63   70.38
2001-07 73.11   64.07   70.72   87.88   60.99   70.88
2001-08 73.17   64.23   71.11   87.65   60.10   71.30
2001-09 73.56   64.58   71.36   89.02   60.21   71.01
2001-10 73.89   65.09   70.89   91.00   58.88   71.03
2001-11 74.08   65.43   70.89   92.12   57.45   71.02
2001-12 74.28   65.70   71.77   92.06   56.75   71.39
2002-01 74.15   65.89   71.94   89.78   58.17   72.04
2002-02 74.21   66.00   71.78   89.53   58.32   72.41
2002-03 74.86   66.25   72.21   90.33   59.43   73.02
2002-04 75.90   67.20   72.71   92.54   60.90   73.28
2002-05 76.16   67.47   73.03   92.96   61.06   73.50
2002-06 76.16   67.63   73.17   92.91   59.87   73.80
2002-07 75.64   67.74   73.60   89.96   60.07   74.23
2002-08 75.90   67.81   74.15   89.82   60.26   74.71
2002-09 76.16   67.95   74.73   90.71   60.77   74.43
2002-10 76.87   68.01   74.85   93.38   61.08   74.42
2002-11 77.00   68.07   75.01   94.69   59.49   74.27
2002-12 77.26   68.26   75.62   94.56   60.04   74.61
2003-01 76.94   68.66   75.92   91.62   61.35   74.96
2003-02 77.07   69.14   75.21   91.57   62.20   75.25
2003-03 77.65   69.38   75.47   92.50   63.05   75.62
2003-04 78.30   69.47   75.43   95.07   61.39   76.17
2003-05 78.24   69.53   75.76   95.52   59.86   76.01
2003-06 78.30   69.59   75.93   95.36   59.52   76.32
2003-07 77.85   69.67   76.71   92.04   60.06   76.86
2003-08 78.24   69.80   77.73   91.81   60.88   77.44
2003-09 78.43   69.92   78.83   92.74   60.63   77.01
2003-10 78.95   70.23   78.54   94.90   59.96   77.12
2003-11 79.21   70.43   78.53   95.94   60.14   76.99
2003-12 79.34   70.57   78.96   95.86   59.96   77.29
2004-01 78.69   70.96   79.25   92.38   60.34   77.59
2004-02 78.76   71.37   78.26   92.21   60.60   77.90
2004-03 79.34   71.57   78.77   93.05   61.49   78.31
2004-04 80.45   72.00   78.98   95.90   62.29   78.94
2004-05 80.90   72.82   79.48   96.49   63.80   78.83
2004-06 81.03   73.00   79.47   96.43   63.79   79.18
2004-07 80.45   73.05   80.04   92.89   64.00   79.69
2004-08 80.84   73.14   80.36   92.80   65.14   80.25
2004-09 80.97   73.24   80.31   93.79   65.18   79.87
2004-10 81.81   73.29   80.25   96.27   66.92   79.90
2004-11 82.00   73.42   80.66   97.23   66.12   79.89
2004-12 81.94   73.55   80.89   97.06   64.50   80.18
2005-01 81.16   73.88   81.54   93.35   63.99   80.50
2005-02 81.35   73.96   81.20   93.16   65.23   80.88

基本上，我真正想要的是选择每一列，然后进行以下操作：(一年中的第一个月/下一年的下一个月)- 1。我想把它转换成一个函数，这样我就可以将该列作为参数添加，然后就会产生神奇的效果。但是我得到了一个错误: NameError: name 'column1‘没有定义

因此，我有以下代码行：

def function(new_columna):
new = new_columna
new_columna = []
cont = 12
for e in range(0,229,12):
    datos = ((hasta_2019.iloc[cont, 0] / hasta_2019.iloc[e, 0] ) - 1)*100
    new_columna.append(datos)
    cont += 12

    
    if cont >= hasta_2019.shape[0]:
        print("terminado")
        break
    return new_columna

使用它，我想创建一个列表，然后用它创建新的dataframe，但是我得到了一个错误

function(_column1_)
--------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-924-fcd7fae2a243> in <module>
----> 1 funcion(Prueba1)

NameError: name '_column1_' is not defined

Answer 1

首先，在您当前的代码中：

def function(new_columna):
new = new_columna
new_columna = []

由于缩进错误，您的函数无法工作：

def function(new_columna):
    new = new_columna
    new_columna = []

但是你不需要一个函数来创建一个简单的列表对象。你只需要一个空的列表，首先：

new_list = []
cont = 12
for e in range(0,229,12):
    datos = ((hasta_2019.iloc[cont, 0] / hasta_2019.iloc[e, 0] ) - 1)*100
    new_list.append(datos)
    cont += 12

创建列表之后，现在可以将新列表作为列添加到现有的数据框架(df)中，如下所示：

df['column2'] = new_list