Is there a way to reject empty rows in Roo?

[billy-whizz]

I have a spreadsheet of members designed as below:

My aim is to upload some columns and exclude others. In this case, I wish to upload only the name, age and email and exclude the others. I have been able to achieve this using the slice method as shown below:

def load_imported_members
    spreadsheet = open_spreadsheet
    spreadsheet.default_sheet = 'Worksheet'
    header = spreadsheet.row(1)
    (2..spreadsheet.last_row).map do |i|
      row = Hash[[header, spreadsheet.row(i)].transpose]
      member = Member.find_by_id(row["id"]) || Member.new
      member.attributes = row.to_hash.slice("id", "name", "age", "email")
      member
    end
  end

The problem is that last_row considers all the rows upto the last one (13), and since there are validations on the form, there are errors due to missing data as a result of the empty rows (which shouldn’t be considered). Is there a way I can upload only specific columns as I have done, yet limit to only the rows that have data?