2.5 Subsetting criteria

Build vector indicating whether each observation is from a shipwreck:

isShipwreck <-
  cleanAmphorae$Site_Name=="Cap del Vol" |
  cleanAmphorae$Site_Name=="Ullastres I" |
  cleanAmphorae$Site_Name=="Port-Vendres 4"

	Workshops	Shipwrecks
	175	48

Build vectors indicating provenance group and whether observations are true outliers (IND, observations with no group assigned). Also, reformat “FabricGroup” and “ChemReferenceGroup”, so true outliers are singled out separately and not as a extra group.

ProvenanceGroup <- c()
isTrueIND <- c()

# coerce the original group variables (factors) into character vectors
# so we can use stringr package to operate on them.
cleanAmphorae$FabricGroup <- 
  as.character(cleanAmphorae$FabricGroup)
cleanAmphorae$ChemReferenceGroup <- 
  as.character(cleanAmphorae$ChemReferenceGroup)

for (i in 1:nrow(cleanAmphorae)){
  groupChem <-
    stringr::str_split(cleanAmphorae$ChemReferenceGroup[i], "-")[[1]]
  groupFabric <-
    stringr::str_split(cleanAmphorae$FabricGroup[i], "-")[[1]]
  group <- ""
  isATrueInd <- FALSE

  if (groupChem[2] == "IND" || groupFabric[2] == "IND") {
    group <- cleanAmphorae$ChemReferenceGroup[i]
    if (!isShipwreck[i]) isATrueInd <- TRUE
    index <- 1
    for (j in 1:length(ProvenanceGroup)){
      if (ProvenanceGroup[j] == paste(group, index, sep = ""))
        index <- index + 1
    }
    group <- paste(group, index, sep = "")
    cleanAmphorae$ChemReferenceGroup[i] <- group
    cleanAmphorae$FabricGroup[i] <- group
  }
  else {
    if (groupChem[1] == "ULL" || 
        groupChem[1] == "PV4" || 
        groupChem[1] == "CDV") {
      group <- cleanAmphorae$ChemReferenceGroup[i]
    }
    else if (groupChem[1] == groupFabric[1]){
      group <- groupChem[1]
    }
  }
  ProvenanceGroup <- c(ProvenanceGroup, group[1])
  isTrueIND <- c(isTrueIND, isATrueInd)
}

	Assigned	Outliers
	205	18