An Index Class for Quarterly Data
"yearqtr" is a class for representing quarterly data.
yearqtr(x) as.yearqtr(x, ...) ## S3 method for class 'character' as.yearqtr(x, format, ...) ## S3 method for class 'yearqtr' format(x, format = "%Y Q%q", ...)
x |
for |
format |
character string specifying format. For coercing to |
... |
arguments passed ot other methods. |
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.
yearqtr and as.yearqtr return the first argument converted to
class yearqtr.
The format method returns a character string representation of
its argument first argument.
Sys.setenv(TZ = "GMT")
x <- as.yearqtr(2000 + seq(0, 7)/4)
x
format(x, "%Y Quarter %q")
as.yearqtr("2001 Q2")
as.yearqtr("2001 q2") # same
as.yearqtr("2001-2") # same
# returned Date is the fraction of the way through
# the period given by frac (= 0 by default)
dd <- as.Date(x)
format.yearqtr(dd)
as.Date(x, frac = 1)
as.POSIXct(x)
suppressWarnings(RNGversion("3.5.0"))
set.seed(1)
zz <- zoo(rnorm(8), x, frequency = 4)
zz
as.ts(zz)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.