zoo (version 1.1-1)

yearqtr: An Index Class for Quaterly Data

Description

"yearqtr" is a class for representing quaterly data.

Usage

yearqtr(x)

Arguments

x

numeric (interpreted as being in years).

Value

• Returns its argument converted to class yearqtr.

Details

The yearqtr class is used to represent quaterly 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. 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".

See Also

yearmon, zoo, zooreg, ts

Examples

x <- yearqtr(2000 + seq(0, 7)/4)
x

# returned Date is the fraction of the way through
# the period given by frac (= 0 by default)
as.Date(x)
as.Date(x, frac = 1)
as.POSIXct(x)

z <- zoo(rnorm(8), x, frequency = 4)
z
as.ts(z)