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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/api.R
\name{CFtime-function}
\alias{CFtime-function}
\alias{CFtime}
\title{Create a CFTime object}
\usage{
CFtime(definition, calendar = "standard", offsets, from, to, by, length.out)
}
\arguments{
\item{definition}{A character string describing the time coordinate.}
\item{calendar}{A character string describing the calendar to use with the
time dimension definition string. Default value is "standard".}
\item{offsets}{Numeric or character vector, optional. When numeric, a vector
of offsets from the origin in the time series. When a character vector,
timestamps in ISO8601 or UDUNITS format.}
\item{from, to}{Optional. Character timestamps in ISO8601 or UDUNITS format.
When \code{from} is given, a sequence of timestamps is generated with \code{from} as
the starting timestamp. Either argument \code{to} or \code{length.out} must be
provided as well. Ignored when argument \code{offsets} is not \code{NULL}.}
\item{by}{Optional. A single character string representing a time interval,
composed of a number and a time unit separated by a space, such as in "6
hours". When argument \code{from} is supplied, argument \code{by} will be the
separation between successive timestamps. Note that the time unit in the
string does not have to be the same as the unit in the \code{definition}
argument but it must be an allowable unit of time. Time interval units of
"months" and "years" are strongly discouraged unless the same time unit is
used in the \code{definition} argument - in all other cases there is a loss of
precision due to the ambiguity in the time units.}
\item{length.out}{Optional. An numeric value that indicates the lengths of
the time series to generate, rounded up if fractional. Ignored when
argument \code{to} is provided.}
}
\value{
An instance of the \code{CFTime} class.
}
\description{
This function creates an instance of the \link{CFTime} class. The arguments to the
call are typically read from a CF-compliant data file with climatological
observations or climate projections. Specification of arguments can also be
made manually in a variety of combinations.
}
\details{
A time series can also be constructed like a sequence. In this case argument
\code{offsets} should be \code{NULL} or missing and arguments \code{from} and \code{by} provided,
with either of arguments \code{to} or \code{length.out} indicating the end of the time
series. Arguments should be named to avoid ambiguity.
}
\examples{
# Using numeric offset values - this is how a netCDF file works
CFtime("days since 1850-01-01", "julian", 0:364)
# A time object with a single defined timestamp
CFtime("hours since 2023-01-01", "360_day", "2023-01-30T23:00")
# A time series from a sequence with an end point
CFtime("days since 2023-01-01", from = "2020-01-01", to = "2023-12-31", by = "12 days")
# A time series from a sequence with a specified length
CFtime("days since 2023-01-01", from = "2020-01-01T03:00:00", by = "6 hr", length.out = 31 * 4)
}
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