The R Project SVN R

\name{write.table}

\alias{write.table}

\title{Data Output}

\description{

  \code{write.table} prints its required argument \code{x} (after

  converting it to a data frame if it is not one already) to

  \code{file}.  The entries in each line (row) are separated by the

  value of \code{sep}.

}

\usage{

write.table(x, file = "", append = FALSE, quote = TRUE, sep = " ",

            eol = "\n", na = "NA", dec = ".", row.names = TRUE,

	    col.names = TRUE, qmethod = c("escape", "double"))

}

\arguments{

  \item{x}{the object to be written, typically a data frame.  If not, it

    is attempted to coerce \code{x} to a data frame.}

  \item{file}{either a character string naming a file or a connection.

    \code{""} indicates output to the console.}

  \item{append}{logical.  If \code{TRUE}, the output is appended to the

    file.  If \code{FALSE}, any existing file of the name is destroyed.}

  \item{quote}{a logical value or a numeric vector.  If \code{TRUE}, any

    character or factor columns will be surrounded by double quotes.  If

    a numeric vector, its elements are taken as the indices of the

    columns to quote.  In both cases, row and column names

    are quoted if they are written. If \code{FALSE}, nothing is quoted.}

  \item{sep}{the field separator string.  Values within each row of

    \code{x} are separated by this string.}

  \item{eol}{the character(s) to print at the end of each line (row).}

  \item{na}{the string to use for missing values in the data.}

  \item{dec}{the string to use for decimal points.}

  \item{row.names}{either a logical value indicating whether the row

    names of \code{x} are to be written along with \code{x}, or a

    character vector of row names to be written.}

  \item{col.names}{either a logical value indicating whether the column

    names of \code{x} are to be written along with \code{x}, or a

    character vector of column names to be written.}

  \item{qmethod}{a character string specifying how to deal with embedded

    double quote characters when quoting strings.  Must be one of

    \code{"escape"} (default), in which case the quote character is

    escaped in C style by a backslash, or \code{"double"}, in which case

    it is doubled.  You can specify just the initial letter.}

}

\details{

  Normally there is no column name for a column of row names.  If

  \code{col.names=NA} a blank column name is added.  This can be used to

  write CSV files for input to spreadsheets.

  \code{write.table} can be slow for data frames with large numbers

  (hundreds or more) of columns: this is inevitable as each column could

  be of a different class and so must be handled separately.

  Function \code{\link[MASS]{write.matrix}} in package \pkg{MASS}

  may be much more efficient if \code{x} is a matrix or can be

  represented in a numeric matrix.

}

\seealso{

  The \dQuote{R Data Import/Export} manual.

  \code{\link{read.table}}, \code{\link{write}}.

  \code{\link[MASS]{write.matrix}}.

}

\examples{

\dontrun{

## To write a CSV file for input to Excel one might use

write.table(x, file = "foo.csv", sep = ",", col.names = NA)

## and to read this file back into R one needs

read.table("file.csv", header = TRUE, sep = ",", row.names=1)

}}

\keyword{print}

\keyword{file}