Question

我正在使用递归神经网络基于以前的风数据进行每小时风速预测。我试图使用.shift将数据向后移动1小时，以生成此数据。我的DateFrame看起来像[this] [1]我的代码是：

import numpy as np
import pandas as pd 
from pandas import DataFrame 

wind_p = [0, 0.03454225, 0.02062136, 0.00186715, 0.01517354, 0.0129046,  
0.02231125, 0.01492537, 0.09646542, 0.28444476]

Speed = [0, 2.25226244, 1.44078451, 0.99174488, 0.71179491, 0.92824542, 1.67776948, 2.96399534, 5.06257161, 7.06504245]

Date = ['2012-01-01 01:00:00' ,'2012-01-01 02:00:00', '2012-01-01 03:00:00', '2012-01-01 04:00:00', 
'2012-01-01 05:00:00', '2012-01-01 06:00:00', '2012-01-01 07:00:00',
'2012-01-01 08:00:00', '2012-01-01 09:00:00', '2012-01-01 10:00:00']

df = pd.DataFrame({'date':Date,'wind_P':wind_p,'Speed':Speed})
dates=[datetime.strptime(x,'%Y-%m-%d %H:%M:%S') for x in Date]


df['t']= [x for x in range(10)]
df['t+1'] = df[Speed].shift(-1)
print(df)

我从中得到的错误消息是：

KeyError                                  Traceback (most recent call last)
<ipython-input-1-bb88ddb20ff4> in <module>()
     18 
     19 df['t']= [x for x in range(10)]
---> 20 df['t+1'] = df[Speed].shift(-1)
     21 print(df)

~/anaconda3_501/lib/python3.6/site-packages/pandas/core/frame.py in __getitem__(self, key)
   1956         if isinstance(key, (Series, np.ndarray, Index, list)):
   1957             # either boolean or fancy integer index
-> 1958             return self._getitem_array(key)
   1959         elif isinstance(key, DataFrame):
   1960             return self._getitem_frame(key)

~/anaconda3_501/lib/python3.6/site-packages/pandas/core/frame.py in _getitem_array(self, key)
   2000             return self.take(indexer, axis=0, convert=False)
   2001         else:
-> 2002             indexer = self.loc._convert_to_indexer(key, axis=1)
   2003             return self.take(indexer, axis=1, convert=True)
   2004 

~/anaconda3_501/lib/python3.6/site-packages/pandas/core/indexing.py in _convert_to_indexer(self, obj, axis, is_setter)
   1229                 mask = check == -1
   1230                 if mask.any():
-> 1231                     raise KeyError('%s not in index' % objarr[mask])
   1232 
   1233                 return _values_from_object(indexer)

KeyError: '[0.         2.25226244 1.44078451 0.99174488 0.71179491 0.92824542\n 1.67776948 2.96399534 5.06257161 7.06504245] not in index'



Help with shifting the data in column `Speed` back by 1 step would be appreciated!

  [1]: https://i.stack.imgur.com/oANWb.jpg

Answer 1

KeyError: '[0.         2.25226244 1.44078451 0.99174488 0.71179491 0.92824542\n 1.67776948 2.96399534 5.06257161 7.06504245] not in index'

该错误表明Speed（列表）正在尝试为df对象建立索引。速度不是有效的索引，因此会导致错误。

您似乎想要使用字符串'Speed'，通过将df[Speed]更改为df['Speed']将其视为df的索引。

Answer 2

In [114]: df['t+1'] = df['Speed'].shift(-1)
#  NOTE:                 ^     ^

In [115]: df
Out[115]:
                  date    wind_P     Speed  t       t+1
0  2012-01-01 01:00:00  0.000000  0.000000  0  2.252262
1  2012-01-01 02:00:00  0.034542  2.252262  1  1.440785
2  2012-01-01 03:00:00  0.020621  1.440785  2  0.991745
3  2012-01-01 04:00:00  0.001867  0.991745  3  0.711795
4  2012-01-01 05:00:00  0.015174  0.711795  4  0.928245
5  2012-01-01 06:00:00  0.012905  0.928245  5  1.677769
6  2012-01-01 07:00:00  0.022311  1.677769  6  2.963995
7  2012-01-01 08:00:00  0.014925  2.963995  7  5.062572
8  2012-01-01 09:00:00  0.096465  5.062572  8  7.065042
9  2012-01-01 10:00:00  0.284445  7.065042  9       NaN

将列数据移回1时发生KeyError

2 个答案: