how to calculate a value from other fields in excel sheet using formulas

I'm using xlrd package for python to generate my excel reports. for some fields, they are a calculations from other fields. I'm using

worksheet.write(1, 2,  '178', formatting )
worksheet.write(1, 3,  '100', formatting )

for the field (1,4) is the SUM of (1,2) and (1,3)

I can do that if I used : worksheet.write(1, 4, '=SUM(A1,B1)', formatting )

but in my case I'm using numbers (col, row) instead of letters (A1).

I tried chr(1)+':1' - chr(1)+':2'

but seems like the letters I'm getting don't reflect the numbers.

Any thoughts will be highly appreciated!

The solution I'm using for now is

value1 = '178'
value2 = '100'
worksheet.write(1, 2,  value1, formatting )
worksheet.write(1, 3,  value2, formatting )
worksheet.write(1, 4, value1+value2  , formatting )

but as you see I'm not using built in excel formulas and the excel user won't see where the value came from. like what was the calculation used?. exactly for finance department.

Thanks!

Solution

Here's a simple iterative version that should handle arbitrary column numbers, adapted from the C# code at this answer:

How to convert a column number (eg. 127) into an excel column (eg. AA)

def column_label(column_number):
    column_labels = []
    column_number = column_number + 1
    while column_number > 0:
        column_number, modulo = divmod(column_number - 1, 26)
        column_labels.append(string.uppercase[modulo])
    return ''.join(reversed(column_labels))

This takes a 0-indexed column number, such as those xlrd and xlwt use. I don't love the conversion to 1-indexed before building the names, but I need to think more about the algorithm before replacing it.