p <- as.POSIXlt(Sys.Date())
Do you mean unclass(p)?
x <- unclass(p)
str(x)
## List of 11
## $ sec : num 0
## $ min : int 0
class(x) <- c("POSIXlt", "POSIXt")
identical(x,p) ## TRUE
If you actually use unlist() then everything gets a bit harder,
because all the elements get coerced to character, and we have to undo
that ...
xx <- unlist(p)
str(xx)
## Named chr [1:11]
xx <- as.list(xx)
not_zone <- names(xx) != "zone"
xx[not_zone] <- as.integer(xx[not_zone])
class(xx) <- c("POSIXlt", "POSIXt")
This is not quite identical to the original object, because the sec
component is numeric (not integer), and because the time zone is
originally an attribute (but gets made into an element of the list); you
could reverse-engineer that with some more work.
On 2026-07-07 7:01 a.m., iagogv via R-help wrote:
Hi all,
From DateTimeClasses help:
Class "POSIXlt" is internally a list [1] of vectors with components
named sec, min, hour for the time, mday, mon, and year, for the date,
wday, yday for the day of the week and day of the year, isdst, a
Daylight Saving Time flag, and sometimes (both _optional_) zone, a
string for the time zone, and gmtoff, offset in seconds from GMT
If I unlist(x), where x is a POSIXlt object, I get that list, internal
representation of x.
Is there an inverse function returning the POSIXlt object from that
list?
Thank you!
Best,
Iago
Links:
------
[1] http://127.0.0.1:25406/library/base/help/list
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