Convert an excel or spreadsheet column letter to its number in Pythonic fashion

Question

Is there a more pythonic way of converting excel-style columns to numbers (starting with 1)?

Working code up to two letters:

Answer 1

Coincise and elegant Ruby version:

def col_num(col_name)
    col_name.split(//).inject(0) { |n, c| n * 26 + c.upcase.ord - "A".ord + 1 }
end