% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/testCharDateTime.r
\name{testCharDateTime}
\alias{testCharDateTime}
\title{testCharDateTime}
\usage{
testCharDateTime(x, p = 0.5, m = 0, convert = FALSE, existing = FALSE)
}
\arguments{
\item{x}{input vector of any type, but interesting cases are for character \code{x}}

\item{p}{minimum proportion of non-missing non-blank values of \code{x} for which the format is one of the formats described before considering \code{x} to be of that type}

\item{m}{if greater than 0, a test is applied: the number of distinct illegal values of \code{x} (values containing a letter or underscore) must not exceed \code{m}, or type \code{character} will be returned.  \code{p} is set to \code{1.0} when \code{m} > 0.}

\item{convert}{set to \code{TRUE} to convert the variable under the dominant format}

\item{existing}{set to \code{TRUE} to return a character string with the current type of variable without examining pattern matches}
}
\value{
if \code{convert=FALSE}, a single character string with the type of \code{x}: \verb{"character", "datetime", "date", "time"}.  If \code{convert=TRUE}, a list with components named \code{type}, \code{x} (converted to \code{POSIXct}, \code{Date}, or \code{chron} times format), and \code{numna}, the number of originally non-\code{NA} values of \code{x} that could not be converted to the predominant format.  If there were any non-covertible dates/times,
the returned vector is given an additional class \code{special.miss} and an
attribute \code{special.miss} which is a list with original character values
(\code{codes}) and observation numbers (\code{obs}).  These are summarized by
\code{describe()}.
}
\description{
Test Character Variables for Dates and Times
}
\details{
For a vector \code{x}, if it is already a date-time, date, or time variable, the type is returned if \code{convert=FALSE}, or a list with that type, the original vector, and \code{numna=0} is returned.  Otherwise if \code{x} is not a character vector, a type of \code{notcharacter} is returned, or a list that includes the original \code{x} and \code{type='notcharacter'}.  When \code{x} is character, the main logic is applied.  The default logic (when \code{m=0}) is to consider \code{x} a date-time variable when its format is YYYY-MM-DD HH:MM:SS (:SS is optional) in more than 1/2 of the non-missing observations.  It is considered to be a date if its format is YYYY-MM-DD or MM/DD/YYYY or DD-MMM-YYYY in more than 1/2 of the non-missing observations (MMM=3-letter month).  A time variable has the format HH:MM:SS or HH:MM.  Blank values of \code{x} (after trimming) are set to \code{NA} before proceeding.
}
\examples{
for(conv in c(FALSE, TRUE)) {
  print(testCharDateTime(c('2023-03-11', '2023-04-11', 'a', 'b', 'c'), convert=conv))
  print(testCharDateTime(c('2023-03-11', '2023-04-11', 'a', 'b'), convert=conv))
  print(testCharDateTime(c('2023-03-11 11:12:13', '2023-04-11 11:13:14', 'a', 'b'), convert=conv))
  print(testCharDateTime(c('2023-03-11 11:12', '2023-04-11 11:13', 'a', 'b'), convert=conv))
  print(testCharDateTime(c('3/11/2023', '4/11/2023', 'a', 'b'), convert=conv))
}
x <- c(paste0('2023-03-0', 1:9), 'a', 'a', 'a', 'b')
y <- testCharDateTime(x, convert=TRUE)$x
describe(y)  # note counts of special missing values a, b
}
\author{
Frank Harrell
}