python - Pandas 中条件的 Loc 函数返回 Nan

Question

我真的不明白为什么它返回 NaN

我有一个 df，我需要根据其他列的值再创建一列，这种方法总是有效的。

train.loc[(train.region == 'Latin America') & (train.sales_channel == 'Online'), 'expense'] = 47
train.loc[(train.region == 'Latin America') & (train.sales_channel == 'Partnerships'), 'expense'] = 63
train.loc[(train.region == 'Latin America') & (train.sales_channel == 'Direct Sales'), 'expense'] = 89
train.loc[(train.region == 'Europe') & (train.sales_channel == 'Online'), 'expense'] = 69

我回来了

Answer 1

尝试以下

train.loc[(train['region'] == 'Latin America') & (train['sales_channel'] == 'Partnerships'),['expense']] = 63