\HeaderA{isNumeric}{Test for Numeric Argument}{isNumeric}
\keyword{programming}{isNumeric}
\begin{Description}\relax
Test whether argument is numeric or a data.frame with numeric columns.
\end{Description}
\begin{Usage}
\begin{verbatim}
isNumeric(x)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x}] any object
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
This function is used to check the validity of arguments for numeric functions.
It is an attempt to emulate the behavior of internal generic math functions.

\code{isNumeric} differs from \code{is.numeric} in that data.frames with all columns numeric are accepted as numeric.
\end{Details}
\begin{Value}
\code{TRUE} or \code{FALSE}
\end{Value}
\begin{Author}\relax
Gordon Smyth
\end{Author}
\begin{SeeAlso}\relax
\code{\LinkA{is.numeric}{is.numeric}}, \code{\LinkA{Math}{Math}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
isNumeric(3)
isNumeric("a")
x <- data.frame(a=c(1,1),b=c(0,1))
isNumeric(x)   # TRUE
is.numeric(x)  # FALSE
\end{ExampleCode}
\end{Examples}