将行添加到具有日期范围、created_at 和今天、python 的 pandas 数据框

Question

我有一个数据框 dataframe，由两列 customer_id 和一个日期列 created_at 组成。

我希望为客户保留在客户群中的每个月添加另一行。

例如，如果 customer_id 是在 7 月创建的，则数据框会在“created_at”和“today”的范围内为该客户添加 4 行额外的行。例如;对于 customer1，我将有 9 行，每个月最多一天，对于 customer2：7 行，而 customer3：4 行。我在想可能像我在下面复制的东西，将 df 与 seqDates 合并的想法......

import pandas as pd
import numpy as np 
df = pd.DataFrame([("customer1", "05-02-2020"), ("customer2","05-04-2020"), ("customer3","04-07-2020")], index=["1","2","3"], columns= ("customer_id","created_at"))
df["created_at"] = pd.to_datetime(df["created_at"])


# create month expansion column 
start = min(df["created_at"])
end = pd.to_datetime("today")
seqDates = pd.date_range(start, end, freq="D")
seqDates = pd.DataFrame(seqDates)
columns = ["created_at"]

Answer 1

试试这个：

import pandas as pd
import datetime
from dateutil.relativedelta import relativedelta
from dateutil import rrule, parser


outList = []
operations_date = datetime.datetime.now().date()
dfDict = df.to_dict(orient='records')
for aDict in dfDict:
    created_at = aDict['created_at']
    start_date = datetime.datetime.strptime(created_at, '%d-%m-%Y').date() - 
                 relativedelta(months = 1)
    end_date   = parser.parse(str(operations_date))
    date_range = list(rrule.rrule(rrule.MONTHLY, bymonthday=1, dtstart=start_date, 
                                  until=end_date)) 
    for aDate in date_range:
        outList.append({'customer_id' : aDict['customer_id'], 'created_at' : aDate})

df = pd.DataFrame(outList)