Pandas 基于布尔函数的切片数据帧

我已将D.F.命名为测试：

      December January    Rating
    0   35.00   35.00      1star
    1   0.00    100.00     2star
    2   38.71   28.46      3star
    3   74.32   61.32      4star
    4   65.39   66.505     3star

---

我想根据以下布尔值过滤除最后一列之外的行：

test[test使用
mean
和
，其中
lt
这里是

  December  January  Rating
0   35.00   35.00     NaN
1   0.00    NaN       NaN
2   38.71   28.46     NaN
3   NaN     NaN       NaN
4   NaN     NaN       NaN

     December January     Rating
    0   35.00   35.00     1star
    1   0.00    NaN       2star
    2   38.71   28.46     3star
    3   NaN     NaN       4star
    4   NaN     NaN       3star

df[['December','January']]=df[['December','January']].where(df.lt(df.mean()))
df
Out[77]: 
   December  January Rating
0     35.00    35.00  1star
1      0.00      NaN  2star
2     38.71    28.46  3star
3       NaN      NaN  4star
4       NaN      NaN  3star