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% File src/library/base/man/data.class.Rd
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% Part of the R package, https://www.R-project.org
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% Copyright 1995-2007 R Core Team
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% Distributed under GPL 2 or later
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\name{data.class}
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\alias{data.class}
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\title{Object Classes}
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\description{
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  Determine the class of an arbitrary \R object.
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}
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\usage{
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data.class(x)
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}
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\arguments{
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  \item{x}{an \R object.}
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}
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\value{
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  character string giving the \emph{class} of \code{x}.
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  The class is the (first element) of the \code{\link{class}}
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  attribute if this is non-\code{NULL}, or inferred from the object's
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  \code{dim} attribute if this is non-\code{NULL}, or \code{mode(x)}.
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  Simply speaking, \code{data.class(x)} returns what is typically useful
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  for method dispatching.  (Or, what the basic creator functions already
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  and maybe eventually all will attach as a class attribute.)
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}
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\note{
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  For compatibility reasons, there is one exception to the rule above:
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  When \code{x} is \code{\link{integer}}, the result of
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  \code{data.class(x)} is \code{"numeric"} even when \code{x} is classed.
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}
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\seealso{
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  \code{\link{class}}
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}
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\examples{
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x <- LETTERS
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data.class(factor(x))                 # has a class attribute
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data.class(matrix(x, ncol = 13))      # has a dim attribute
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data.class(list(x))                   # the same as mode(x)
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data.class(x)                         # the same as mode(x)
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stopifnot(data.class(1:2) == "numeric") # compatibility "rule"
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}
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\keyword{classes}
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\keyword{methods}