如何创建指示器列以指示数据框中先前条目的特定更改？

Question

情况：

我目前有一个客户端数据框，按 CLIENT_ID and CURRENT_DATE_STATUS.CLIENT_ID 排序，如下所示：

CLIENT_ID	CURRENT_DATE_STATUS	STATUS
10002	2017-07-21	STARTED
10002	2017-07-21	STARTED
10002	2018-07-01	CHURNED
10002	2018-07-01	CHURNED
10002	2019-01-01	RESTARTED
11811	2019-08-15	STARTED
11811	2019-08-15	STARTED
11811	2019-12-31	RESTARTED
22101	2020-03-11	STARTED
22101	2020-03-11	STARTED
22101	2020-03-11	STARTED
22101	2020-11-01	CHURNED
22300	2018-05-06	STARTED
22300	2018-05-06	STARTED

问题：

我如何创建指示器 Boolean 1 or 0 列来指示：

如果之前的 STATUS 条目已更改为每个 CLIENT_ID 的 CHURNED or RESTARTED。

Objective:

生成的数据框如下所示：

CLIENT_ID	CURRENT_DATE_STATUS	STATUS	STOPPED
10002	2017-07-21	STARTED	0
10002	2017-07-21	STARTED	0
10002	2018-07-01	CHURNED	1
10002	2018-07-01	CHURNED	0
10002	2019-01-01	RESTARTED	1
11811	2019-08-15	STARTED	0
11811	2019-08-15	STARTED	0
11811	2019-12-31	RESTARTED	1
22101	2020-03-11	STARTED	0
22101	2020-03-11	STARTED	0
22101	2020-03-11	STARTED	0
22101	2020-11-01	CHURNED	1
22300	2018-05-06	STARTED	0
22300	2018-05-06	STARTED	0

用于生成所述数据框的代码：

import pandas as pd

data = {'CLIENT_ID':[10002,10002,10002,10002,10002,11811,11811,11811,22101,22101,22101,22101,22300,22300],
'CURRENT_DATE_STATUS':['2017-07-21','2017-07-21','2018-07-01','2018-07-01','2019-07-01','2019-08-15','2019-08-15','2019-12-31','2020-03-11','2020-03-11','2020-03-11','2020-11-01','2018-05-06','2018-05-06'],
'STATUS':['STARTED','STARTED','CHURNED','CHURNED','RESTARTED','STARTED','STARTED','RESTARTED','STARTED','STARTED','STARTED','CHURNED','STARTED','STARTED']}
df = pd.DataFrame(data)

Answer 1

您可以通过 Series.eq with shifted per groups by DataFrameGroupBy.shift for not equalSeries.ne 比较 eqaul 的实际值，对于按位 AND 通过 & 进行链接，对于位 OR 通过 | 进行最后一次链接转换为整数：

s = df.groupby('CLIENT_ID')['STATUS'].shift()
m1 = df['STATUS'].eq('RESTARTED') & s.ne('RESTARTED')
m2 = df['STATUS'].eq('CHURNED') & s.ne('CHURNED')

df['STOPPED'] = (m1 | m2).astype(int)
print (df)
    CLIENT_ID CURRENT_DATE_STATUS     STATUS  STOPPED
0       10002          2017-07-21    STARTED        0
1       10002          2017-07-21    STARTED        0
2       10002          2018-07-01    CHURNED        1
3       10002          2018-07-01    CHURNED        0
4       10002          2019-07-01  RESTARTED        1
5       11811          2019-08-15    STARTED        0
6       11811          2019-08-15    STARTED        0
7       11811          2019-12-31  RESTARTED        1
8       22101          2020-03-11    STARTED        0
9       22101          2020-03-11    STARTED        0
10      22101          2020-03-11    STARTED        0
11      22101          2020-11-01    CHURNED        1
12      22300          2018-05-06    STARTED        0
13      22300          2018-05-06    STARTED        0

另一种解决方案是比较前一个移位值，然后如果匹配 Series.isin 中的列表，最后一个链 & 按位 AND:

m3 = df.groupby('CLIENT_ID')['STATUS'].shift().ne(df['STATUS'])
m4 = df['STATUS'].isin(["CHURNED", "RESTARTED"])

df['STOPPED'] = (m3 & m4).astype(int)
print (df)

    CLIENT_ID CURRENT_DATE_STATUS     STATUS  STOPPED
0       10002          2017-07-21    STARTED        0
1       10002          2017-07-21    STARTED        0
2       10002          2018-07-01    CHURNED        1
3       10002          2018-07-01    CHURNED        0
4       10002          2019-07-01  RESTARTED        1
5       11811          2019-08-15    STARTED        0
6       11811          2019-08-15    STARTED        0
7       11811          2019-12-31  RESTARTED        1
8       22101          2020-03-11    STARTED        0
9       22101          2020-03-11    STARTED        0
10      22101          2020-03-11    STARTED        0
11      22101          2020-11-01    CHURNED        1
12      22300          2018-05-06    STARTED        0
13      22300          2018-05-06    STARTED        0

如何创建指示器列以指示数据框中先前条目的特定更改？

How to create an indicator column to indicate specific change from a previous entry in a dataframe?

python

dataframe

pandas

pandas-groupby