xts (version 0.14.1)

tclass: Get or Replace the Class of an xts Object's Index

Description

Generic functions to get or replace the class of an xts object's index.

Usage

tclass(x, ...)
# S3 method for default
tclass(x, ...)
# S3 method for xts
tclass(x, ...)
tclass(x) <- value
# S3 method for default
tclass(x) <- value
indexClass(x)
indexClass(x) <- value
# S3 method for xts
tclass(x) <- value

Value

A vector containing the class of the object's index.

Arguments

x

An xts object.

...

Arguments passed to other methods.

value

The new index class (see Details for valid values).

Author

Jeffrey A. Ryan

Details

Internally, an xts object's index is a numeric value corresponding to seconds since the epoch in the UTC timezone. The index class is stored as the tclass attribute on the internal index. This is used to convert the internal index values to the desired class when the index function is called.

The tclass function retrieves the class of the internal index, and the tclass<- function sets it. The specified value for tclass<- must be one of the following character strings: "Date", "POSIXct", "chron", "yearmon", "yearqtr", or "timeDate".

See Also

index() has more information on the xts index, tformat() details how the index values are formatted when printed, and tzone() has more information about the index timezone settings.

The following help pages describe the characteristics of the valid index classes: POSIXct(), Date(), chron(), yearmon(), yearqtr(), timeDate()

Examples

x <- timeBasedSeq('2010-01-01/2010-01-02 12:00')
x <- xts(seq_along(x), x)

y <- timeBasedSeq('2010-01-01/2010-01-03 12:00/H')
y <- xts(seq_along(y), y, tzone = "America/New_York")

# Changing the tclass *changes* the internal index values
head(y)          # the index has times
head(.index(y))
tclass(y) <- "Date"
head(y)          # the index prints as a Date
head(.index(y))  # the internal index is truncated