python - Get Excel-Style Column Names from Column Number

Question

This is the code for providing the COLUMN name when the row and col ID is provided but when I give values like row = 1 and col = 104, it should return CZ, but it returns D@

row = 1
col = 104
div = col
column_label = str()
while div:
    (div, mod) = divmod(div, 26)
    column_label = chr(mod + 64) + column_label

print column_label

What is wrong with what I am doing?

(This code is in reference for EXCEL Columns, where I provide the Row,Column ID value and expect the ALPHABETIC value for the same.)

Answer 1

EDIT: I feel I must admit, as pointed out by a few others—who never left me comments—that the previous version of my answer (which you accepted) had a bug that prevented it from properly handling column numbers greater than 702 (corresponding to Excel column 'ZZ'). So, in the interests of correctness, that's been fixed in the code below, which now contains a loop just like many of the other answers do.

It's quite likely you never used the previous version with large enough column numbers to have encountered the issue. FWIW, the MS specs for the current version of Excel say it supports worksheets with up to 16,384 columns (Excel column 'XFD').

LETTERS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'

def excel_style(row, col):
    """ Convert given row and column number to an Excel-style cell name. """
    result = []
    while col:
        col, rem = divmod(col-1, 26)
        result[:0] = LETTERS[rem]
    return ''.join(result) + str(row)

if __name__ == '__main__':
    addresses = [(1,  1), (1, 26),
                 (1, 27), (1, 52),
                 (1, 53), (1, 78),
                 (1, 79), (1, 104),
                 (1, 18253), (1, 18278),
                 (1, 702),  # -> 'ZZ1'
                 (1, 703),  # -> 'AAA1'
                 (1, 16384), # -> 'XFD1'
                 (1, 35277039)]

    print('({:3}, {:>10}) --> {}'.format('row', 'col', 'Excel'))
    print('==========================')
    for row, col in addresses:
        print('({:3}, {:10,}) --> {!r}'.format(row, col, excel_style(row, col)))

Output:

(row,       col) --> Excel
========================
(  1,         1) --> 'A1'
(  1,        26) --> 'Z1'
(  1,        27) --> 'AA1'
(  1,        52) --> 'AZ1'
(  1,        53) --> 'BA1'
(  1,        78) --> 'BZ1'
(  1,        79) --> 'CA1'
(  1,       104) --> 'CZ1'
(  1,     18253) --> 'ZZA1'
(  1,     18278) --> 'ZZZ1'
(  1,       702) --> 'ZZ1'
(  1,       703) --> 'AAA1'
(  1,     16384) --> 'XFD1'
(  1,  35277039) --> 'BYEBYE1'