How to output the last element by original sequences when using dataframe.last() after resample?

Question

I have a dataframe as below and doing resample:

df = pd.DataFrame([1, 2, 3, 4, 5], index=[datetime(2021, 3, 2, hour=11),
                                           datetime(2021, 3, 2, hour=12),
                                           datetime(2021, 3, 2, hour=13),
                                           datetime(2021, 3, 2, hour=1),
                                           datetime(2021, 3, 2, hour=2)])

r= df.resample('1D')
print(r.first())
print(r.last())

And the result is

            0
2021-03-02  4
            0
2021-03-02  3

Now I need r.first() to be datetime(2021, 3, 2, hour=11):1 and r.last() to be datetime(2021, 3, 2, hour=2):5 as the original sequences shows, but not the results after sorted. How can this be obtained?

Answer 1

For prevent sorting is possible use groupby with dates:

r= df.groupby(df.index.date)
print(r.first())
print(r.last())
            0
2021-03-02  1
            0
2021-03-02  5