code: func (dt *DbfTable) FieldValueByName(row int, fieldName string) (value string, err error) {
  	if fieldIndex, entryFound := dt.fieldMap[fieldName]; entryFound {
  		return dt.FieldValue(row, fieldIndex), err
  	}
  	err = errors.New("Field name \"" + fieldName + "\" does not exist")
  	return
  }
docs: // FieldValueByName returns the value of a field given row number and name provided