Similar to Dates' firstdayof* and lastdayof*, I introduce to you penultimatedayof*; a useful function to find the second-to-last day of a measure of time.
Unlike Dates' *dayof* functions, I have extended functionality to find, for example, the penultimate Tuesday of a measure of time. We have also extended some of Dates' *dayof* functions to allow this functionality.
See also jakewilliami/pt for a command-line implementation using logic from this package.
julia> using Dates, PenultimateDays
julia> d = today()
2022-06-24
julia> penultimatedayofweek(d) # second-to-last day of the week
2022-06-25
julia> penultimatedayofmonth(d) # second-to-last day of the month
2022-06-29
julia> penultimatedayofmonth(d, Tuesday) # second-to-last Tuesday of the month
2022-06-21
julia> penultimatedayofquarter(d) # second-to-last day of the quarter
2022-06-29
julia> penultimatedayofquarter(d, Tuesday) # second-to-last Tuesday of the quarter
2022-06-21
julia> penultimatedayofyear(d) # second-to-last day of the year
2022-12-31
julia> penultimatedayofyear(d, Tuesday) # second-to-last Tuesday of the year
2022-12-20We have also extended the Dates standard library to allow specification of day for *dayof* functions:
julia> using Dates, PenultimateDays
julia> d = today()
2022-06-24
julia> firstdayofmonth(d, Tuesday)
2022-06-07
julia> lastdayofmonth(d, Tuesday)
2022-06-28