Sorry I missed this part. Also I’m not sure what a “calendar week” is. Is that the index of the week in the calendar year? If so this could work:
S.from_list([~D[2023-01-01], ~D[2023-01-08], ~D[2023-02-23]])
# #Explorer.Series<
# Polars[3]
# date [2023-01-01, 2023-01-08, 2023-02-23]
# >
|> S.transform(&Date.day_of_year/1)
# #Explorer.Series<
# Polars[3]
# integer [1, 8, 54]
# >
|> S.quotient(7)
# #Explorer.Series<
# Polars[3]
# integer [0, 1, 7]
# >
