Efficient way to create matrix that shows if data exits per day

So I have a dataset containing different ID's and the time the data was created.

    ID              Date
0   123123          2021-03-24 12:43:13.494000+00:00
1   123412          2021-03-24 12:43:13.494000+00:00
2   123123          2021-03-24 12:43:15.935000+00:00
3   234234          2021-03-24 12:43:15.935000+00:00
4   432424          2021-03-24 12:43:13.494000+00:00

The goal should be to validate that there is at least one data row for every id for every given day. What I did so far is converting the timestamps to dates like this:

0         2021-03-24
1         2021-03-24
2         2021-03-24
3         2021-03-24
4         2021-03-24

Now I missing a solution to create a matrix that tells me if for the given ID on the given date a data row of this data exists or not: The data frame creation looks like this:

df = pd.DataFrame(index=df['id'].unique(),columns=df['date'].sort_values().unique())

which creates this matrix:

    2021-03-19  2021-03-20  2021-03-21  2021-03-22  2021-03-23  2021-03-24  2021-03-25
12341   NaN NaN NaN NaN NaN NaN NaN
12312   NaN NaN NaN NaN NaN NaN NaN
12324   NaN NaN NaN NaN NaN NaN NaN
12345   NaN NaN NaN NaN NaN NaN NaN
12345   NaN NaN NaN NaN NaN NaN NaN
... ... ... ... ... ... ... ...
12399   NaN NaN NaN NaN NaN NaN NaN
12394   NaN NaN NaN NaN NaN NaN NaN
34567   NaN NaN NaN NaN NaN NaN NaN
98764   NaN NaN NaN NaN NaN NaN NaN
10023   NaN NaN NaN NaN NaN NaN NaN

sure I could just use loops to now fill the values, however this would be a a really inefficient way to do it.. I think there is a better way and I am super sure somebody can tell me how so I can learn it for the future.

Thank you very much!