Returns the time at which a permanently stored version of a dataset
(object) was last modified.
USAGE:
dataset.date(name, where=1, meta = 0, date.format=10)
REQUIRED ARGUMENTS:
name
character string naming a dataset stored on database
where.
OPTIONAL ARGUMENTS:
where
a number identifying a database in the search list.
meta
if supplied, for example, as
"methods" or
"help", look in the
corresponding meta-database instead of the ordinary database.
date.format
integer specifying in which format the dataset date should be returned.
Currently recognized values are
1 for an integer like
717805635,
measuring seconds since 1 January 1970 00:00 GMT;
10 for a string like
"Tue Sep 29 15:27:15 1992"; and
11 for "92.09.29 15:27".
VALUE:
if
where refers to a directory database, the time of the last
modification to the permanently stored version of
this dataset. Note that datasets are not permanently stored until the end
of a top level expression unless you use
synchronize() or
assign(..., immediate=T)
to force early storage.
The return value
"NA" (or
-1 for integer format) means that the
dataset does not exist on the database.
"0" (or
0 for integer format)
is returned for the special dataset
.Random.seed, whether it exists or
not. Zero is also returned for any object in a non-directory database.
SEE ALSO:
,
,
.
EXAMPLES:
x <- 10
dataset.date("x")
d <- dataset.date("x", date.format=1) # as number
x <- 20
# Compute time between assignemnts:
dataset.date("x", date.format=1) - d