The "yearqtr"
class is used to represent quarterly data. Internally it holds
the data as year plus 0 for Quarter 1, 1/4 for Quarter 2
and so on in order that its internal representation is the same as
ts
class with frequency = 4
. If x
is not in this
format it is rounded via floor(4*x + .0001)/4
.
as.yearqtr.character
uses a default format of "%Y Q%q"
,
"%Y q%q"
or "%Y-%q"
according to whichever matches.
%q
accepts the numbers 1-4 (possibly with leading zeros). Due to
this %q
does not match to single digits only and consequently
formats such as as.yearqtr("Q12000", "Q%q%Y")
are ambiguous and
do not work (i.e., result in NA
).
There are coercion methods available for various classes including:
default coercion to "yearqtr"
(which coerces to "numeric"
first)
and coercion from "yearqtr"
to "Date"
(see below), "POSIXct"
,
"POSIXlt"
, "numeric"
, "character"
and "jul"
.
The last one is from the frame
package on CRAN.
There is an is.numeric
method which returns FALSE
.
There is also a date
method for as.yearqtr
usable with objects
created with package date
.
Sys.yearqtr()
returns the current year/month and methods for
min
, max
and range
are defined (by defining
a method for Summary
).
A yearqtr
mean
method is also defined.
Certain methods support a frac
argument. See yearmon
.