twdtw (version 1.0-1)

date_to_numeric_cycle: Convert Date/POSIXct to a Numeric Cycle

Description

This function takes a date or datetime and converts it to a numeric cycle. The cycle can be specified in units of years, months, days, hours, minutes, or seconds. When cycle_length is a string, time_scale only changes the unit in which the result is expressed. When cycle_length is numeric, time_scale and origin are used to compute the elapsed time.

Usage

date_to_numeric_cycle(x, cycle_length, time_scale, origin = NULL)

Value

The numeric cycle value(s) corresponding to x.

Arguments

x

A vector of dates or datetimes to convert. If not of type Date or POSIXct, the function attempts to convert it.

cycle_length

The length of the cycle. Can be a numeric value or a string specifying the units ('year', 'month', 'day', 'hour', 'minute', 'second'). When numeric, the cycle length is in the same units as time_scale. When a string, it specifies the time unit of the cycle.

time_scale

Specifies the time scale for the conversion. Must be one of 'year', 'month', 'day', 'hour', 'minute', 'second'. When cycle_length is a string, time_scale changes the unit in which the result is expressed. When cycle_length is numeric, time_scale is used to compute the elapsed time in seconds.

origin

For numeric cycle_length, the origin must be specified. This is the point from which the elapsed time is computed. Must be of the same class as x.

Examples

date_to_numeric_cycle(Sys.time(), "year", "day") # Returns the day of the year
date_to_numeric_cycle(Sys.time(), "day", "hour") # Returns the hour of the day