删除NaN'Cell'而不丢弃整个ROW(Pandas,Python3)

Question

现在我有这样的DF

 Word       Word2          Word3
 Hello      NaN            NaN
 My         My Name        NaN
 Yellow     Yellow Bee     Yellow Bee Hive
 Golden     Golden Gates   NaN
 Yellow     NaN            NaN

我希望的是从我的数据框中删除所有NaN细胞.所以最后,它看起来像这样,'Yellow Bee Hive'已经移动到第1行(类似于从excel中的列中删除单元格时发生的情况):

   Word       Word2             Word3
1  Hello      My Name        Yellow Bee Hive
2  My         Yellow Bee       
3  Yellow     Golden Gates             
4  Golden       
5  Yellow    

不幸的是,这些都不起作用,因为他们删除了整条行!

 df = df[pd.notnull(df['Word','Word2','Word3'])]

要么

 df = df.dropna() 

有人有什么建议吗？我应该重新索引桌子吗？

Answer 1

import numpy as np
import pandas as pd
import functools

def drop_and_roll(col, na_position='last', fillvalue=np.nan):
    result = np.full(len(col), fillvalue, dtype=col.dtype)
    mask = col.notnull()
    N = mask.sum()
    if na_position == 'last':
        result[:N] = col.loc[mask]
    elif na_position == 'first':
        result[-N:] = col.loc[mask]
    else:
        raise ValueError('na_position {!r} unrecognized'.format(na_position))
    return result

df = pd.read_table('data', sep='\s{2,}')

print(df.apply(functools.partial(drop_and_roll, fillvalue='')))

产量

     Word         Word2            Word3
0   Hello       My Name  Yellow Bee Hive
1      My    Yellow Bee                 
2  Yellow  Golden Gates                 
3  Golden                               
4  Yellow