Однострочные тесты протестированы в Python 2.7.1 и 3.5.2
excel_col_num = lambda a: 0 if a == '' else 1 + ord(a[-1]) - ord('A') + 26 * excel_col_num(a[:-1])
excel_col_name = lambda n: '' if n <= 0 else excel_col_name((n - 1) // 26) + chr((n - 1) % 26 + ord('A'))
Аналогично мультилинии
def excel_column_name(n):
"""Number to Excel-style column name, e.g., 1 = A, 26 = Z, 27 = AA, 703 = AAA."""
name = ''
while n > 0:
n, r = divmod (n - 1, 26)
name = chr(r + ord('A')) + name
return name
def excel_column_number(name):
"""Excel-style column name to number, e.g., A = 1, Z = 26, AA = 27, AAA = 703."""
n = 0
for c in name:
n = n * 26 + 1 + ord(c) - ord('A')
return n
def test (name, number):
for n in [0, 1, 2, 3, 24, 25, 26, 27, 702, 703, 704, 2708874, 1110829947]:
a = name(n)
n2 = number(a)
a2 = name(n2)
print ("%10d %-9s %s" % (n, a, "ok" if a == a2 and n == n2 else "error %d %s" % (n2, a2)))
test (excel_column_name, excel_column_number)
test (excel_col_name, excel_col_num)
Все тесты печатают
0 ok
1 A ok
2 B ok
3 C ok
24 X ok
25 Y ok
26 Z ok
27 AA ok
702 ZZ ok
703 AAA ok
704 AAB ok
2708874 EXCEL ok
1110829947 COLUMNS ok