code: public static DiscreteVariable fromCsvColumn(String variableName, 
        String filename, String delimiter, int columnNumber) {
      List<String> values = IoUtils.readColumnFromDelimitedFile(filename, columnNumber, delimiter);
      return new DiscreteVariable(variableName, values);
    }
docs: Constructs a variable containing all of the values in {@code columnNumber}
  of the delimited file {@code filename}. {@code delimiter} separates the
  columns of the file.
  
  @param variableName
  @param filename
  @param delimiter
  @param columnNumber
  @return