希望我的例子大一点，我的代码在这里：
import pandas as pd
import numpy as np
import io
t = """
name date
a 2005-08-31
a 2005-09-20
a 2005-11-12
a 2005-12-31
a 2006-03-31
a 2006-06-25
a 2006-07-23
a 2006-09-28
a 2006-12-21
a 2006-12-27
a 2007-07-23
a 2007-09-21
a 2007-03-15
a 2008-04-12
a 2008-06-21
a 2008-06-11
b 2005-08-31
b 2005-09-23
b 2005-11-12
b 2005-12-31
b 2006-03-31
b 2006-06-25
b 2006-07-23
b 2006-09-28
b 2006-12-21
b 2006-12-27
b 2007-07-23
b 2007-09-21
b 2007-03-15
b 2008-04-12
b 2008-06-21
b 2008-06-11
"""
data=pd.read_csv(io.StringIO(t),delimiter=' ')#5 space here
data
我想做的是找到一年中的最后一天，开始
2005-7-1，结束2006-06-30，开始2006-7-1和结束2007-6-30…等等。我期望的结果是：
name date
a 2006-06-25 #the last day of the 2005/7/01 -2006/06/31
a 2007-03-15 #the last day of the 2006/7/01 -2007/06/31
a 2008-06-21 #the last day of the 2007/7/01 -2008/06/31
b 2006-06-25 #the last day of the 2005/7/01 -2006/06/31
b 2007-03-15 #the last day of the 2006/7/01 -2007/06/31
b 2008-06-21 #the last day of the 2007/7/01 -2008/06/31
怎么能解决这个问题？我想我应该使用
custom 最佳答案
无需使用单个groupby回滚即可完成此操作：
In [11]: data.date = pd.to_datetime(data.date, format="%Y-%m-%d")
In [12]: df.groupby(["name", pd.Grouper(key="date", freq="AS-JUL")])["date"].max()
Out[12]:
name date
a 2005-07-01 2006-06-25
2006-07-01 2007-03-15
2007-07-01 2008-06-21
b 2005-07-01 2006-06-25
2006-07-01 2007-03-15
2007-07-01 2008-06-21
Name: date, dtype: datetime64[ns]
关于python - 如何获取自定义间隔中的最后日期？ - Pandas ，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/46859942/