我有一个这样的数据框:
° item_name item_category scraping_date price
0 Michel1 Category1 2018-04-14 21.0
1 Michel1 Category1 2018-04-16 42.1
2 Michel1 Category1 2018-04-17 84.0
3 Michel1 Category1 2018-04-19 126.2
4 Michel1 Category1 2018-04-20 168.3
5 Michel1 Category2 2018-04-23 21.2
6 Michel1 Category2 2018-05-08 42.0
7 Michel1 Category2 2018-03-26 84.1
8 Michel1 Category2 2018-03-31 126.2
9 Michel1 Category2 2018-04-01 168.3
10 Michel2 Category1 2018-04-04 21.0
11 Michel2 Category1 2018-04-05 42.1
12 Michel2 Category1 2018-04-09 84.2
13 Michel2 Category1 2018-04-11 126.3
14 Michel2 Category1 2018-04-12 168.4
15 Michel2 Category2 2018-04-13 21.0
16 Michel2 Category2 2018-05-03 42.1
17 Michel2 Category2 2018-04-25 84.2
18 Michel2 Category2 2018-04-28 126.3
19 Michel2 Category2 2018-04-29 168.4
我想按商品名称和类别分组,按周重新采样,并获得每周的平均价格。最后,我想在这样的字典中输出日期:
[
{
"item_name": "Michel1",
"item_category": "Category1",
"prices": [
{"week": "1", "average": "84.2"},
{"week": "2", "average": "84.2"}
]
},
{
"item_name": "Michel1",
"item_category": "Category2",
"prices": [
{"week": "1", "average": "84.2"},
{"week": "2", "average": "84.2"}
]
},....
]
我附带了一些要分组的东西,并得到了平均值,但我无法将其转化为字典:
df["price"] = df["price"].astype(float)
df["scraping_date"] = pd.to_datetime(df["scraping_date"])
df.set_index("scraping_date").groupby(["item_name","item_category"])["price"].resample("W").mean()
如果我执行.to_dict()
,我得到了,这几乎不是我想要的:
{('Michel1', 'Category1', Timestamp('2017-12-03 00:00:00')): 20.0,
('Michel1', 'Category1', Timestamp('2017-12-10 00:00:00')): 20.0,
('Michel1', 'Category2', Timestamp('2017-12-17 00:00:00')): 20.0,
('Michel1', 'Category2', Timestamp('2017-12-24 00:00:00')): 20.0,
('Michel2', 'Category1', Timestamp('2017-12-31 00:00:00')): 20.0,
('Michel2', 'Category1', Timestamp('2018-01-07 00:00:00')): 20.0,
}
我不能保证速度,与apply
一起使用分组
df['Week']=pd.to_datetime(df.scraping_date).dt.week
df.groupby(['item_name','item_category']).apply(lambda x : x.groupby(['Week']).price.mean().to_frame('average')
.reset_index().to_dict('r')).to_frame('price').reset_index().to_dict('r')
Out[51]:
[{'item_category': 'Category1',
'item_name': 'Michel1',
'price': [{'Week': 15.0, 'average': 21.0},
{'Week': 16.0, 'average': 105.15}]},
{'item_category': 'Category2',
'item_name': 'Michel1',
'price': [{'Week': 13.0, 'average': 126.2},
{'Week': 17.0, 'average': 21.2},
{'Week': 19.0, 'average': 42.0}]},
{'item_category': 'Category1',
'item_name': 'Michel2',
'price': [{'Week': 14.0, 'average': 31.55},
{'Week': 15.0, 'average': 126.3}]},
{'item_category': 'Category2',
'item_name': 'Michel2',
'price': [{'Week': 15.0, 'average': 21.0},
{'Week': 17.0, 'average': 126.3},
{'Week': 18.0, 'average': 42.1}]}]