Trying to cut pandas series by even intervals (and sum those values)

pd.cut() error

For the following code snippet:

```
    u = pd.Series(u, index=m.index)
    u = u.groupby(level=['TimeCreated']).sum()
    u.name = 'FcoUMined'
    # sum by years (12 time steps)
    print u
    u_year = u.groupby(pd.cut(u.index, np.arange(0, 12, 12)))['FcoUMined'].sum()
    print u_year
```

This error:


TimeCreated
50             19.609390
68              6.733351
81              6.733351
95              6.733351
110             6.733351
124             6.733351
138             6.733351
152             6.733351
166             6.733351
180             6.733351
194             6.733351
208             6.733351
222             6.733351
236             6.733351
250             6.733351
264             6.733351
278             6.733351
292             6.733351
306             6.733351
320             6.733351
334             6.733351
348             6.733351
362             6.733351
376             6.733351
390             4.961361
404             6.733351
418             5.552024
432             6.733351
446             6.142688
460             6.733351
474             6.733351
488             4.961361
502             6.733351
516             5.552024
530             6.733351
Name: FcoUMined, dtype: float64
---------------------------------------------------------------------------
NotImplementedError                       Traceback (most recent call last)
<ipython-input-21-0ff429aa2b0f> in <module>()
     29     return rtn
     30 
---> 31 cym.exec_code("FcoUMined[:]", db)

/home/opotowsky/.local/lib/python2.7/site-packages/cymetric/execution.pyc in exec_code(code, db, write)
    215     glb = {}
    216     loc = ExecutionContext(evaler=evaler)
--> 217     exec(code, glb, loc)

<string> in <module>()

/home/opotowsky/.local/lib/python2.7/site-packages/cymetric/execution.pyc in __getitem__(self, key)
    132                 elif isinstance(k, str_types):
    133                     conds.append(parse_cond(k))
--> 134         return self.evaler.eval(self.name, conds=conds)
    135 
    136 

/home/opotowsky/.local/lib/python2.7/site-packages/cymetric/evaluator.pyc in eval(self, metric, conds)
     57             s = None if d is None else raw_to_series(d, dep[1], dep[2])
     58             series.append(s)
---> 59         raw = m(series=series, conds=conds, known_tables=self.known_tables)
     60         if raw is None:
     61             return raw

/home/opotowsky/.local/lib/python2.7/site-packages/cymetric/metrics.pyc in __call__(self, series, conds, known_tables, *args, **kwargs)
     75             if self.name in known_tables:
     76                 return self.db.query(self.name, conds=conds)
---> 77             return f(series)
     78 
     79     Cls.__name__ = str(name)

<ipython-input-21-0ff429aa2b0f> in fco_u_mined(series)
     24     # sum by years (12 time steps)
     25     print u
---> 26     u_year = u.groupby(pd.cut(u.index, np.arange(0, 12, 12)))['FcoUMined'].sum()
     27     print u_year
     28     rtn = u_year.reset_index()

/usr/lib/python2.7/dist-packages/pandas/core/groupby.pyc in __getitem__(self, key)
    489 
    490     def __getitem__(self, key):
--> 491         raise NotImplementedError('Not implemented: %s' % key)
    492 
    493     def _make_wrapper(self, name):

NotImplementedError: Not implemented: FcoUMined