我有一个示例数据框

Account     Date         Amount 
10          2020-06-01   100
10          2020-06-11   500
10          2020-06-21   600
10          2020-06-25   900
10          2020-07-11   1000
10          2020-07-15   600
11          2020-06-01   100
11          2020-06-11   200
11          2020-06-21   500
11          2020-06-25   1500
11          2020-07-11   2500
11          2020-07-15   6700

我想获取每个帐户每 30 天间隔的行数，即

Account     Date         Amount 
10          2020-06-01   1
10          2020-06-11   2
10          2020-06-21   3
10          2020-06-25   4
10          2020-07-11   4
10          2020-07-15   4
11          2020-06-01   1
11          2020-06-11   2
11          2020-06-21   3
11          2020-06-25   4
11          2020-07-11   4
11          2020-07-15   4

我尝试过石斑鱼和重新采样，但这些给了我每 30 天的计数，而不是滚动计数。
提前致谢！

回答

def get_rolling_amount(grp, freq):
    return grp.rolling(freq, on="Date", closed="both").count()


df["Date"] = pd.to_datetime(df["Date"])
df["Amount"] = df.groupby("Account").apply(get_rolling_amount, "30D").values
print(df)

def get_rolling_amount(grp, freq):
    return grp.rolling(freq, on="Date", closed="both").count()


df["Date"] = pd.to_datetime(df["Date"])
df["Amount"] = df.groupby("Account").apply(get_rolling_amount, "30D").values
print(df)