Python 大熊猫翻滚了几天,得到了一笔钱
这是我的数据帧Python 大熊猫翻滚了几天,得到了一笔钱,python,pandas,dataframe,pandas-groupby,Python,Pandas,Dataframe,Pandas Groupby,这是我的数据帧 d= {'dates': ['2020-07-16','2020-07-15','2020-07-14','2020-07-13','2020-07-16','2020-07-15','2020-07-14','2020-07-13'], 'location':['Paris','Paris','Paris','Paris','NY','NY','NY','NY'],'T':[100,200,300,400,10,20,30,40]} df = pandas.Data
d= {'dates': ['2020-07-16','2020-07-15','2020-07-14','2020-07-13','2020-07-16','2020-07-15','2020-07-14','2020-07-13'],
'location':['Paris','Paris','Paris','Paris','NY','NY','NY','NY'],'T':[100,200,300,400,10,20,30,40]}
df = pandas.DataFrame(data=d)
df['dates']=pandas.to_datetime(df['dates'])
df
我想计算过去2天(包括当前日期)内给定位置的一些T
值。
这是我想要的熊猫:
dates location T SUM2D
0 2020-07-16 Paris 100 300
1 2020-07-15 Paris 200 500
2 2020-07-14 Paris 300 700
3 2020-07-13 Paris 400 NaN
4 2020-07-16 NY 10 30
5 2020-07-15 NY 20 50
6 2020-07-14 NY 30 70
7 2020-07-13 NY 4 NaN
我试着玩弄这句话,但没有成功:
df['SUM2D'] = df.set_index('dates').groupby('location').rolling(window=2, freq='D').sum()['T'].values
尝试在索引之前对数据帧进行排序:
df = df.sort_values(['location','dates']).set_index('dates')
df['SUM2D'] = df.groupby('location')['T'].rolling(window=2, freq='D').sum().values
df[::-1]
结果集:
location T SUM2D
dates
2020-07-16 Paris 100 300.0
2020-07-15 Paris 200 500.0
2020-07-14 Paris 300 700.0
2020-07-13 Paris 400 NaN
2020-07-16 NY 10 30.0
2020-07-15 NY 20 50.0
2020-07-14 NY 30 70.0
2020-07-13 NY 40 NaN
更紧凑、更优雅的解决方案是使用变换
:
df['SUM2D'] = df.sort_values(['dates']).groupby('location')['T'].transform(lambda x: x.rolling(2, 2).sum())
结果是:
dates location T SUM2D
0 2020-07-16 Paris 100 300.0
1 2020-07-15 Paris 200 500.0
2 2020-07-14 Paris 300 700.0
3 2020-07-13 Paris 400 NaN
4 2020-07-16 NY 10 30.0
5 2020-07-15 NY 20 50.0
6 2020-07-14 NY 30 70.0
7 2020-07-13 NY 40 NaN
只需将df[:-1]添加到第一个解决方案中,即可对日期进行重新排序。谢谢刚刚编辑-重新排序日期。如果解决方案是好的,请接受它作为一个答案。
dates location T SUM2D
0 2020-07-16 Paris 100 300.0
1 2020-07-15 Paris 200 500.0
2 2020-07-14 Paris 300 700.0
3 2020-07-13 Paris 400 NaN
4 2020-07-16 NY 10 30.0
5 2020-07-15 NY 20 50.0
6 2020-07-14 NY 30 70.0
7 2020-07-13 NY 40 NaN