endpoints
returns a numeric vector corresponding to the
last observation in each period specified by on
, with a
zero added to the beginning of the vector, and the index of the last
observation in x
at the end.
Valid values for the argument on
include: “us” (microseconds),
“microseconds”, “ms” (milliseconds),
“milliseconds”, “secs” (seconds),
“seconds”, “mins” (minutes), “minutes”,
“hours”, “days”, “weeks”, “months”, “quarters”,
and “years”.