Pandas Group By Time With Specified Start Time With Non Integer Minutes

I have a dataframe with one hour long signals. I want to group them in 10 minutes buckets. The problem is that the starting time is not precisely a 'multiple' of 10 minutes, theref

Solution 1:

base accepts a float argument. In addition to the minutes, you must also consider the seconds.

base = ts.index[0].minute + ts.index[0].second/60
ts.groupby(pd.Grouper(freq=interval, base=base)).size()

2011-01-01 00:05:30    600
2011-01-01 00:15:30    600
2011-01-01 00:25:30    600
2011-01-01 00:35:30    600
2011-01-01 00:45:30    600
2011-01-01 00:55:30    600
Freq: 10T, dtype: int64