如果将列表转换为Series，那么它将正常工作:

If you convert the list to a Series then it will just work:

datasetTest.loc[:,'predict_close'] = pd.Series(test_pred_list)

示例:

In[121]:
df = pd.DataFrame({'a':np.arange(3)})
df

Out[121]: 
   a
0  0
1  1
2  2

In[122]:
df.loc[:,'b'] = pd.Series(['a','b'])
df

Out[122]: 
   a    b
0  0    a
1  1    b
2  2  NaN

文档将其称为通过放大设置讨论添加或扩展，但也可以在长度小于预先存在的索引的情况下使用.

The docs refer to this as setting with enlargement which talks about adding or expanding but it also works where the length is less than the pre-existing index.

要处理索引不是从0开始还是实际上不是int的地方:

To handle where the index doesn't start at 0 or in fact is not an int:

In[126]:
df = pd.DataFrame({'a':np.arange(3)}, index=np.arange(3,6))
df

Out[126]: 
   a
3  0
4  1
5  2

In[127]:
s = pd.Series(['a','b'])
s.index = df.index[:len(s)]
s

Out[127]: 
3    a
4    b
dtype: object

In[128]:
df.loc[:,'b'] = s
df

Out[128]: 
   a    b
3  0    a
4  1    b
5  2  NaN

如果希望致电fillna