Is there a way to change my file path automatically and apply a function in R?

Question

I'm looking to apply the 'multiple_sounds' function to a list of .WAV files from a folder using R. This is my current code:

##### 1 #####
setwd("E:/Audiomoth Files/Winter/Rural/Emma/_1")
multiple_sounds(directory = "E:/Audiomoth Files/Winter/Rural/Emma/_1", resultfile = "ndsi_results.csv", soundindex = "ndsi", no_cores = "-2")
multiple_sounds(directory = "E:/Audiomoth Files/Winter/Rural/Emma/_1", resultfile = "adi_results.csv", soundindex = "acoustic_diversity", no_cores = "-2")
multiple_sounds(directory = "E:/Audiomoth Files/Winter/Rural/Emma/_1", resultfile = "aei_results.csv", soundindex = "acoustic_evenness", no_cores = "-2")
multiple_sounds(directory = "E:/Audiomoth Files/Winter/Rural/Emma/_1", resultfile = "aci_results.csv", soundindex = "acoustic_complexity", no_cores = "-2")
multiple_sounds(directory = "E:/Audiomoth Files/Winter/Rural/Emma/_1", resultfile = "H_results.csv", soundindex = "bioacoustic_index", no_cores = "-2")

##### 2 #####
setwd("E:/Audiomoth Files/Winter/Rural/Emma/_2")
multiple_sounds(directory = "E:/Audiomoth Files/Winter/Rural/Emma/_2", resultfile = "ndsi_results.csv", soundindex = "ndsi", no_cores = "-2")
multiple_sounds(directory = "E:/Audiomoth Files/Winter/Rural/Emma/_2", resultfile = "adi_results.csv", soundindex = "acoustic_diversity", no_cores = "-2")
multiple_sounds(directory = "E:/Audiomoth Files/Winter/Rural/Emma/_2", resultfile = "aei_results.csv", soundindex = "acoustic_evenness", no_cores = "-2")
multiple_sounds(directory = "E:/Audiomoth Files/Winter/Rural/Emma/_2", resultfile = "aci_results.csv", soundindex = "acoustic_complexity", no_cores = "-2")
multiple_sounds(directory = "E:/Audiomoth Files/Winter/Rural/Emma/_2", resultfile = "H_results.csv", soundindex = "bioacoustic_index", no_cores = "-2")

This works, but at the moment I have to copy and paste this code each time for each folder(_1, _2, _3 etc.) of which there are 623, so doing this manually is very time consuming.

Is there a way I can automate the file path to change the directory to go to _3, _4, _5 automatically and apply the function in a loop all the way to the 623rd folder?

Thank you in advance

Answer 1

I would suggest writing a utility function and using the directory as an input:

apply_wav_index = function(
  dir,
  index = c("ndsi", "acoustic_diversity", "acoustic_evenness", "acoustic_complexity", "bioacoustic_index"),
  labels = c("ndsi", "adi", "aei", "aci", "H"),
  ...
) {
  if(length(index) != length(labels)) stop("Must provide same number of labels and indexes")
  for(i in seq_along(index)) {
    multiple_sounds(
      directory = dir,
      resultfile = paste0(dir, "/", labels[i], "_results.csv"),
      soundindex = index[i],
      ...
    )
  }
}

Then you should be able to call it like this:

for(i in 1:6) {
  apply_wav_index(dir = paste0("E:/Audiomoth Files/Winter/Rural/Emma/_", i), no_cores = "-2")
}

You could also potentially generate the list of directories with list.dirs().