Excel列名変換をPythonで

excelcol.py

def col2row(col):
    """
    >>> col2row('B')
    2
    >>> col2row('Z')
    26
    >>> col2row('AA')
    27
    >>> col2row('AZ')
    52
    >>> col2row('BA')
    53
    >>> col2row('ZZ')
    702
    >>> col2row('AAA')
    703
    """
    return sum((ord(c) - 64) * (26 ** i)
               for i, c in enumerate(reversed(col)))

def row2col(row):
    """
    >>> row2col(2)
    'B'
    >>> row2col(26)
    'Z'
    >>> row2col(27)
    'AA'
    >>> row2col(52)
    'AZ'
    >>> row2col(53)
    'BA'
    >>> row2col(702)
    'ZZ'
    >>> row2col(703)
    'AAA'
    """
    n = (row - 1) % 26 + 1
    c = chr(n + 64)
    r = (row - n) / 26
    return c if r == 0 else row2col(r) + c

if __name__ == '__main__':
    import sys
    a = sys.argv
    if len(a) == 1:
        import doctest
        doctest.testmod()
    else:
        if a[1].isdigit():
            print row2col(int(a[1]))
        else:
            print col2row(a[1])