筛选出dataframe中全为数字的列的值

In [1]: import pandas as pd

In [2]: import numpy as np

In [3]: students = [ ('jack', 'Apples' , 34) ,
   ...:              ('Riti', 'Mangos'  , 31) ,
   ...:              ('Aadi', 'Grapes' , 30) ,
   ...:              ('Sonia', 'Apples', 32) ,
   ...:              ('Lucy', 'Mangos'  , 33) ,
   ...:              ('Mike', 'Apples' , 35)
   ...:               ]

In [4]: #Create a DataFrame object
   ...: dfObj = pd.DataFrame(students, columns = ['Name' , 'Product', 'Sale'])

In [5]: condition = dfObj.apply(lambda s: pd.to_numeric(s, errors='coerce').notn
   ...: ull().all()).to_dict()

In [6]: dfObj[[k for k,v in condition.items() if v]]
Out[6]:
   Sale
0    34
1    31
2    30
3    32
4    33
5    35