R/fmt_gridref.R

In BiologicalRecordsCentre/sparta: Trend Analysis for Unstructured Data

fmt_gridref <-
function(gridref, gr_fmt = NULL){
  # Setup object to hold output grid refs
  gr_out = rep(NA, length(gridref))
  # convert gridref string to upper case
  gridref = toupper(gridref)
  # Replace any spaces, punctuation or control characters
  gridref = gsub("[[:space:][:cntrl:][:punct:]]", "", gridref)
  # Check that gridref conforms to grid reference pattern after removals
  # Get indices of gridrefs which are in a valid format
  gr_inds = which(grepl("^[[:upper:]]{1,2}[[:digit:]]{2,}([[:upper:]]?|[[:upper:]]{2})$", gridref))
  # Copy valid gridrefs to output object
  gr_out[gr_inds] = gridref[gr_inds]
  # Extract components where gr_fmt is not NULL (1 = Whole gridref minus tet/quad codes, 2 = Inital letter(s), 3 = Digits only, 4 = Tetrad/Quad only, 5 = Tetrad only, 6 = Quadrant only)
  if(!is.null(gr_fmt)){
    gr_out = gsub("^(([[:upper:]]{1,2})([[:digit:]]{2,}))(([[:upper:]]?)|([[:upper:]]{2}))$", paste("\\",gr_fmt, sep=""), gr_out)
  }
  # Return formatted gridref
  return(gr_out)
}