从汇总类别创建新列

Question

我有一个数据框，看起来像：

    SK_ID_CURR  CREDIT_ACTIVE
0   215354  Closed
1   215354  Active
2   215354  Active
3   215354  Active
4   215354  Active
5   215354  Active
6   215354  Active
7   162297  Closed
8   162297  Closed
9   162297  Active

我想汇总每个ID的有效信用和封闭信用的数量，然后为Active_credits，Closed_credits创建一个新列，并列出每个ID对应的有效信用和封闭信用的数量。

Answer 1

您可以使用pandas.crosstab，从而避免了建议的中介步骤：

res = pd.crosstab(df['SK_ID_CURR'], df['CREDIT_ACTIVE'])

print(res)

CREDIT_ACTIVE  Active  Closed
SK_ID_CURR                   
162297              1       2
215354              6       1

Answer 2

您可以使用pd.DataFrame.groupby

df1.groupby(['SK_ID_CURR','CREDIT_ACTIVE']).size()

输出：

SK_ID_CURR  CREDIT_ACTIVE
162297      Active           1
            Closed           2
215354      Active           6
            Closed           1