如何根据Python中的两个条件更改列的值

我有一个数据集，其中我有游戏时间和事件时间

  EVENT     GAME
  0:34      0:43
  NaN       0:23
  2:34      3:43
  NaN       4:50

我想用GAME列中的值替换GAME<0.24的EVENT列中的NaN

 df['EVENT'][(df['GAME'] < '0:24') & (df['EVENT'] == 'NaN')] = df['GAME']

df['EVENT'][（df['GAME']<'0:24'）和（df['EVENT']='NaN'）]=df['GAME']

我试过这个，但不起作用。对不起，如果这是显而易见的。我是Python新手

您可以用于检查

NaN

：

df.loc[(df['GAME'] < '0:24') & (df['EVENT'].isnull()), 'EVENT'] = df['GAME']
print (df)

  EVENT  GAME
0  0:34  0:43
1  0:23  0:23
2  2:34  3:43
3   NaN  4:50

或：

mask = (df['GAME'] < '0:24') & (df['EVENT'].isnull())
df['EVENT'] = df['EVENT'].mask(mask, df['GAME'])
print (df)
  EVENT  GAME
0  0:34  0:43
1  0:23  0:23
2  2:34  3:43
3   NaN  4:50

df['EVENT'] = np.where(mask, df['GAME'], df['EVENT'])
print (df)
  EVENT  GAME
0  0:34  0:43
1  0:23  0:23
2  2:34  3:43
3   NaN  4:50