How to group a Series by values in pandas?

Question

I currently have a pandas Series with dtype Timestamp, and I want to group it by date (and have many rows with different times in each group).

Answer 1

You should convert it to a DataFrame, then add a column that is the date(). You can do groupby on the DataFrame with the date column.

df = pandas.DataFrame(s, columns=["datetime"])
df["date"] = df["datetime"].apply(lambda x: x.date())
df.groupby("date")

Then "date" becomes your index. You have to do it this way because the final grouped object needs an index so you can do things like select a group.