I currently have a dataframe that looks like: I am trying to figure out how to do the following, and just don't know how to start.... For each DAY, cumsum the volume.. After this, group the data by time of day (ie, 10min intervals). If a day doesn't have that interval (sometimes gaps), then it should just be treated as 0. Any help would really be appreciated!

Pandas - Cumsum over time periods + groupby time

I currently have a dataframe that looks like:

I am trying to figure out how to do the following, and just don't know how to start....

For each DAY, cumsum the volume..
After this, group the data by time of day (ie, 10min intervals). If a day doesn't have that interval (sometimes gaps), then it should just be treated as 0.

Any help would really be appreciated!