TypeError：仅对 DatetimeIndex、TimedeltaIndex 或 PeriodIndex 有效，但得到了“RangeIndex”的实例，我不知道为什么

Question

I've this dataframe in pandas

        key                              date  story_point  Story point
0   SOF-158  2019-06-04 09:51:01.143000+02:00          3.0          3.0
1   SOF-152  2019-05-24 09:10:23.483000+02:00          3.0          3.0
2   SOF-151  2019-05-24 09:10:14.978000+02:00          3.0          3.0
3   SOF-150  2019-05-24 09:10:23.346000+02:00          3.0          3.0
4   SOF-149  2019-05-24 09:10:23.024000+02:00          3.0          3.0
5   SOF-148  2019-05-24 09:10:23.190000+02:00          3.0          3.0
6   SOF-146  2019-05-24 09:10:22.840000+02:00          5.0          5.0
7   SOF-142  2019-04-15 10:50:03.946000+02:00          2.0          2.0
8   SOF-141  2019-03-29 10:54:08.677000+01:00          2.0          2.0
9   SOF-139  2019-04-15 10:44:56.033000+02:00          3.0          3.0
10  SOF-138  2019-04-15 10:48:53.874000+02:00          3.0          3.0
11  SOF-129  2019-03-28 11:56:17.221000+01:00          5.0          5.0
12  SOF-128  2019-03-29 11:34:47.552000+01:00          1.0          1.0
13  SOF-106  2019-03-25 10:15:43.231000+01:00          5.0          5.0
14  SOF-105  2019-03-25 10:15:43.252000+01:00          3.0          3.0
15  SOF-103  2019-03-29 11:55:45.984000+01:00          8.0          8.0
16  SOF-102  2019-03-25 10:15:43.210000+01:00          8.0          8.0
17  SOF-101  2019-03-25 10:15:43.179000+01:00          8.0          8.0
18  SOF-100  2019-03-29 12:08:16.525000+01:00         13.0         13.0
19   SOF-99  2019-03-19 12:48:58.168000+01:00          1.0          1.0
20   SOF-98  2019-03-19 12:47:28.172000+01:00         13.0         13.0
21   SOF-91  2019-03-08 11:53:19.456000+01:00          3.0          3.0
22   SOF-89  2019-04-05 09:32:39.517000+02:00          8.0          8.0
23   SOF-88  2019-03-25 10:15:42.927000+01:00          5.0          5.0
24   SOF-87  2019-04-05 09:32:25.519000+02:00          8.0          8.0

At certain point I need to group by week, so I used resample .

weekly_summary["story_point"] = df.story_point.resample('W').sum()

But I have this error, and I can't figure out why

Traceback (most recent call last):
  File "main.py", line 98, in <module>
    main()
  File "main.py", line 44, in main
    analyze_project(project)
  File "main.py", line 70, in analyze_project
    weekly_summary["story_point"] = df.story_point.resample('W').sum()
  File "/Users/xxxx/anaconda/envs/xxx/lib/python3.6/site-packages/pandas/core/generic.py", line 8449, in resample
    level=level,
  File "/Users/xxx/anaconda/envs/xxx/lib/python3.6/site-packages/pandas/core/resample.py", line 1306, in resample
    return tg._get_resampler(obj, kind=kind)
  File "/Users/xxx/anaconda/envs/xxxx/lib/python3.6/site-packages/pandas/core/resample.py", line 1443, in _get_resampler
    "but got an instance of %r" % type(ax).__name__
TypeError: Only valid with DatetimeIndex, TimedeltaIndex or PeriodIndex, but got an instance of 'RangeIndex'

Answer 1

Convert column date to datetimes and add parameter on to resample :

df['date'] = pd.to_datetime(df['date'])
weekly_summary = df.story_point.resample('W', on='date').sum()

If need new column:

weekly_summary['weekly'] = df.story_point.resample('W', on='date').transform('sum')

Or create DatetimeIndex :

df['date'] = pd.to_datetime(df['date'])
df = df.set_index('date') 
weekly_summary = df.story_point.resample('W').sum()

If need new column:

weekly_summary['weekly'] = df.story_point.resample('W').transform('sum')

Answer 2

The first part of jezrael's answer was giving me KeyError: 'The grouper name date is not found' . It turns out that on= argument can be used only if resample() is called on a dataframe (not on a column). So the following works.

# for weekly aggregate
weekly_summary = df.resample('W', on='date')['story_point'].sum()

# if you want to assign the summary back to df
df['weekly'] = df.resample('W', on='date')['story_point'].transform('sum')

If the index is datetime, then resample() can be called on a column, so

weekly_summary = df.set_index('date')['story_point'].resample('W').sum()

works just fine.