LightLogR (version 0.9.2)

log_zero_inflated: Add a defined number to a numeric and log transform it

Description

Frequently, light exposure data need to be log-transformed. Because light exposure data frequently also contain many zero-values, adding a small value avoids losing those observations. Must be applied with care and reported.

exp_zero_inflated() is the reverse function to log_zero_inflated().

Usage

log_zero_inflated(x, offset = 0.1, base = 10)
exp_zero_inflated(x, offset = 0.1, base = 10)

Value

a transformed numeric vector

Arguments

x

A numeric vector

offset

the amount to add to x, by default 0.1

base

The logarithmic base, by default 10

References

Johannes Zauner, Carolina Guidolin, Manuel Spitschan (2025) How to deal with darkness: Modelling and visualization of zero-inflated personal light exposure data on a logarithmic scale. bioRxiv. doi: https://doi.org/10.1101/2024.12.30.630669

Examples

c(0, 1, 10, 100, 1000, 10000) |> log_zero_inflated()

#For use in a function
sample.data.environment |> 
  dplyr::filter(Id == "Participant") |> 
  dplyr::group_by(Date = lubridate::wday(Datetime, label = TRUE, week_start = 1)) |> 
  dplyr::summarize(
  TAT250 = duration_above_threshold(log_zero_inflated(MEDI), 
                                    Datetime, 
                                    threshold = log_zero_inflated(250)
                                    )
                   )
                   

#Calling exp_zero_inflated on data transformed with log_zero_inflated yields to the original result
c(0, 1, 10, 100, 1000, 10000) |> log_zero_inflated() |> exp_zero_inflated()