dse (version 2006.10-1)

tframe: Extract or Set a tframe

Description

Extract or set the tframe of an object.

Usage

tframe(x)
    ## S3 method for class 'default':
tframe(x)
    ## S3 method for class 'ts':
tframe(x)
    tframe(x) <- value
    ## S3 method for class 'default':
tframe(x) <- value    ## S3 method for class 'ts':
tframe(x) <- value
    tframed(x, tf=NULL, names = NULL)
    ## S3 method for class 'default':
tframed(x, tf = NULL, names = NULL)
    is.tframe(x)
    is.tframed(x)

Arguments

x

an object (to which a tframe is assigned in assignment methods).

value

a tframe.

tf

a tframe object or a tframed object from which a tframe is taken.

names

optional vector of strings to specify new series names.

Value

• Depends.

Details

The first usage returns the tframe of a tframed object. The assignment methods and tframed set the tframe of an object. is.tframe returns a logical. The pure tframe approach is to set a "tframe" attribute for an object. This attribute has a class which indicates the time framing which is used. The the time frame information is often secondary, in the sense that it does not describe the object structure, but only provides some additional information which is useful for doing time based operations on the data, plotting, and printing the object. By putting this in an attribute, the objects class can be used for indicating other information about the structure of the object. For these pure tframe objects the default tframe and code{tframe<-} will often be adequate. The generic/method approach allows for special case (like TSdata where the tframe information is not an attribute of the object, but rather an attribute of the data matrices which are elements of the object).

The generic/method approach also allows for (faking) tframe assignment and extraction with classes like rts, ctc, its, ts, and others which may appear, that try to make the time description part of the object class. (Not a "tframe" approach.) The problem is to extract real tframes and also fake these other classes and old style tsp objects so they look like tfamed objects. Another approach would be to mutilate these objects and force them really be tframed objects (to have a tframe attribute), but that risks conflicting with other (non tframe) code which used the objects. This faking is accomplished by specific methods of the classes, and for old style tsp objects it is built into the default.

This tframed constructor is simply a shortcut for assigning the tframe (tframe(x) <- tf) and series names (seriesNames(x) <- names) to an object, but never assigns NULL values, so the result is guaranteed to be a code{tframed} object. It is like ts but enables the tframe library's methods for handling time. If the tf argument is a tframed object rather than a tframe, then the code{tframe} is extracted and used. If the names argument is not mode "character" of appropriate length, then seriesNames(names) is used. These make it simple to assign the time frame and names of one object to another by z <- tframed(x, tf=y, names=y). is.tframed returns TRUE if a tframe() can extract a tframe from the object. This is true for many objects which are not truly tframed (like ts objects), since tframe() tries fairly hard to build a tframe for the object.

See Also

tfstart, tfend, tffrequency, tfperiods, tftime, tfdiff

Examples

z <- tframe(ts(rnorm(100), start=c(1982,1), frequency=12))
    is.tframe(z)
    zz <- tframed(matrix(rnorm(200), 100,2), tf=z)
    is.tframed(zz)
    zzz <- tframed(matrix(rnorm(200), 100,2), tf=zz)
    is.tframed(zzz)
    tframe(zzz)