load_blast.R

load_blast <- function(blastfile, indexcols = c("queryID"), 
            column_names = c("queryID",  "subjectID", "percent.identity", "alignment.length", "mismatches", 
                            "gap.openings", "qstart", "qend", "sstart", "send", "evalue", "bitscore")) {
  # check index columns
  for (ival in indexcols) {
    if (!ival %in% column_names) {
      stop(paste("bad values in the indexcols. only valid column names can be used:", paste(column_names, collapse = " ")))
    }
  }

  dt <- data.table::fread(input=blastfile, header=FALSE, col.names = column_names, sep="\t")
  data.table::setkeyv(dt, cols = indexcols)

  return(dt)
}