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\name{csv.get}
\alias{csv.get}
\title{Read Comma-Separated Text Data Files}
\description{
Read comma-separated text data files, allowing optional translation
to lower case for variable names after making them valid S names.
There is a facility for reading long variable labels as one of the
rows. If labels are not specified and a final variable name is not
the same as that in the header, the original variable name is saved as
a variable label. Uses \code{read.csv} if the \code{data.table}
package is not in effect, otherwise calls \code{fread}.
}
\usage{
csv.get(file, lowernames=FALSE, datevars=NULL, datetimevars=NULL,
dateformat='\%F',
fixdates=c('none','year'), comment.char="", autodates=TRUE,
allow=NULL, charfactor=FALSE,
sep=',', skip=0, vnames=NULL, labels=NULL, \dots)
}
\arguments{
\item{file}{the file name for import.}
\item{lowernames}{set this to \code{TRUE} to change variable names to
lower case.}
\item{datevars}{character vector of names (after \code{lowernames} is
applied) of variables to consider as a factor or character vector
containing dates in a format matching \code{dateformat}. The
default is \code{"\%F"} which uses the yyyy-mm-dd format.}
\item{datetimevars}{character vector of names (after \code{lowernames}
is applied) of variables to consider to be date-time variables, with
date formats as described under \code{datevars} followed by a space
followed by time in hh:mm:ss format. \code{chron} is used to store
such variables. If all times in the variable
are 00:00:00 the variable will be converted to an ordinary date variable.}
\item{dateformat}{for \code{cleanup.import} is the input format (see
\code{\link{strptime}})}
\item{fixdates}{for any of the variables listed in \code{datevars}
that have a \code{dateformat} that \code{cleanup.import} understands,
specifying \code{fixdates} allows corrections of certain formatting
inconsistencies before the fields are attempted to be converted to
dates (the default is to assume that the \code{dateformat} is followed
for all observation for \code{datevars}). Currently
\code{fixdates='year'} is implemented, which will cause 2-digit or
4-digit years to be shifted to the alternate number of digits when
\code{dateform} is the default \code{"\%F"} or is \code{"\%y-\%m-\%d"},
\code{"\%m/\%d/\%y"}, or \code{"\%m/\%d/\%Y"}. Two-digits years are
padded with \code{20} on the left. Set \code{dateformat} to the
desired format, not the exceptional format.}
\item{comment.char}{a character vector of length one containing a
single character or an empty string. Use '""' to turn off the
interpretation of comments altogether.}
\item{autodates}{Set to true to allow function to guess at which
variables are dates}
\item{allow}{a vector of characters allowed by \R that should not be
converted to periods in variable names. By default, underscores in
variable names are converted to periods as with \R before version
1.9.}
\item{charfactor}{set to \code{TRUE} to change character variables to
factors if they have fewer than n/2 unique values. Blanks and null
strings are converted to \code{NA}s.}
\item{sep}{field separator, defaults to comma}
\item{skip}{number of records to skip before data start. Required if
\code{vnames} or \code{labels} is given.}
\item{vnames}{number of row containing variable names, default is one}
\item{labels}{number of row containing variable labels, default is no labels}
\item{\dots}{arguments to pass to \code{read.csv} other than
\code{skip} and \code{sep}.}
}
\details{
\code{csv.get} reads comma-separated text data files, allowing optional
translation to lower case for variable names after making them valid S
names. Original possibly non-legal names are taken to be variable
labels if \code{labels} is not specified. Character or factor
variables containing dates can be converted to date variables.
\code{cleanup.import} is invoked to finish the job.
}
\value{a new data frame.}
\author{Frank Harrell, Vanderbilt University}
\seealso{
\code{\link{sas.get}}, \code{\link{data.frame}},
\code{\link{cleanup.import}}, \code{\link{read.csv}},
\code{\link{strptime}}, \code{\link{POSIXct}}, \code{\link{Date}},
\code{\link[data.table]{fread}}
}
\examples{
\dontrun{
dat <- csv.get('myfile.csv')
# Read a csv file with junk in the first row, variable names in the
# second, long variable labels in the third, and junk in the 4th row
dat <- csv.get('myfile.csv', vnames=2, labels=3, skip=4)
}
}
\keyword{manip}
\keyword{IO}
\keyword{file}
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