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Convert time to radians

mm_to_radian.Rd

This function converts time values into radians, which is often used in circular statistics and time-of-day analyses.

Usage

mm_to_radian(data, times, format = "%H:%M:%S", time_zone = "UTC")

Arguments

data

A data frame containing a column with time values. Optional. If NULL, the times parameter is treated as a standalone vector.

times

A column name in the data or a vector of time values to be converted. Time values should be in a format recognized by as.POSIXct().

format

A string specifying the format of the time values, using the standard POSIX formatting syntax. Default is "%H:%M:%S".

time_zone

A string specifying the time zone for interpreting the time values. Default is "UTC".

Value

If data is provided, the function returns the input data frame with an additional column named time_radian. If data is not provided, the function returns a numeric vector of time values converted to radians.

Details

This function converts time values into radians based on a 24-hour clock:

  • A full day (24 hours) corresponds to \(2\pi\) radians.

  • The fractional time of the day is calculated as: $$\text{Fraction of the day} = \frac{\text{hours}}{24} + \frac{\text{minutes}}{1440} + \frac{\text{seconds}}{86400}$$

For example, for a time of 23 hours, 6 minutes, and 12 seconds: $$\text{Fraction of the day} = \frac{23}{24} + \frac{6}{1440} + \frac{12}{86400}$$

To convert this fraction into radians: $$\text{Radians} = \text{Fraction of the day} \times 2\pi$$

Examples

if (FALSE) { # \dontrun{
  # Convert a standalone vector of time values
  times <- c("00:00:00", "06:00:00", "12:00:00", "18:00:00")
  mm_to_radian(times = times, format = "%H:%M:%S")

  # Convert a column of time values in a data frame
  data <- data.frame(times = c("00:00:00", "06:00:00", "12:00:00", "18:00:00"))
  mm_to_radian(data = data, times = times, format = "%H:%M:%S")
} # }