多索引列上的熊猫，fillna答案

【问题标题】：pandas, fillna on multiindex columns多索引列上的熊猫，fillna
【发布时间】：2020-03-02 17:05:13
【问题描述】：

index_tuples=[]

for distance in ["near", "far"]:
    for vehicle in ["bike", "car"]:
        index_tuples.append([distance, vehicle])

index = pd.MultiIndex.from_tuples(index_tuples, names=["distance", "vehicle"])
df = pd.DataFrame(index=["city"], columns = index)



d = {(x,y):my_home_city[x][y] for x in my_home_city for y in my_home_city[x]}
df.loc['my_home_city',:]=d
df
Out[994]: 
distance     near       far     
vehicle      bike  car bike  car
city          NaN  NaN  NaN  NaN
my_home_city    1    0    0    1

我想做df['near']['bike'].fillna(False, inplace=True)

它说

试图在数据帧的切片副本上设置值

请参阅文档中的注意事项： http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy

【问题讨论】：

标签： pandas dataframe

【解决方案1】：

我认为inplace 不是很好的做法，请检查this 和this，因此将选定的列分配回tuple：

df[('near', 'bike')] = df[('near', 'bike')].fillna(False)
print (df)
distance       near       far     
vehicle        bike  car bike  car
city          False  NaN  NaN  NaN
my_home_city      1  0.0  0.0  1.0

但你的解决方案应该改变：

df[('near', 'bike')].fillna(False, inplace=True)

【讨论】：