python pandas: diff between 2 dates in a groupby

[bluedragon]

Hi all,

I'm trying to implement this example:

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import pandas as pd import io df = pd.read_csv(io.StringIO('''transactionid;event;datetime;info 1;START;2017-04-01 00:00:00; 1;END;2017-04-01 00:00:02;foo1 2;START;2017-04-01 00:00:02; 3;START;2017-04-01 00:00:02; 2;END;2017-04-01 00:00:03;foo2 4;START;2017-04-01 00:00:03; 3;END;2017-04-01 00:00:03;foo3 4;END;2017-04-01 00:00:04;foo4'''), sep=';', parse_dates=['datetime'])   df.datetime = pd.to_datetime(df.datetime)   funcs = {     'datetime':{         'start_date':   'min',         'end_date':     'max',         'duration':     lambda x: x.max() - x.min(),     },     'info':             'last' }   df.groupby(by='transactionid')['datetime','info'].agg(funcs).reset_index()   print(df)

The expected output should be:

Output:
   transactionid           start_date             end_date  duration  info
0              1  2017-04-01 00:00:00  2017-04-01 00:00:02  00:00:02  foo1
1              2  2017-04-01 00:00:02  2017-04-01 00:00:03  00:00:01  foo2
2              3  2017-04-01 00:00:02  2017-04-01 00:00:03  00:00:01  foo3
3              4  2017-04-01 00:00:03  2017-04-01 00:00:04  00:00:01  foo4

Using python3.7 and I'm getting the following error:

Error:
python.py:24: FutureWarning: Indexing with multiple keys (implicitly converted to a tuple of keys) will be deprecated, use a list instead.
  df.groupby(by='transactionid')['datetime','info'].agg(funcs).reset_index()
Traceback (most recent call last):
  File "python.py", line 24, in <module>
    df.groupby(by='transactionid')['datetime','info'].agg(funcs).reset_index()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pandas/core/groupby/generic.py", line 928, in aggregate
    result, how = self._aggregate(func, *args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/pandas/core/base.py", line 342, in _aggregate
    raise SpecificationError("nested renamer is not supported")
pandas.core.base.SpecificationError: nested renamer is not supported

Any idea to solve this issue?

Thanks a lot