So I was using openpyxl for all my Excel projects, but now I have to work with .xls files, so I was forced to change library. I've chosen pyexcel cuz it seemed to be fairly easy and well documented. So I've gone through hell with creating hundreds of variables, cuz there is no .index property, or something.

What I want to do now is to read the column in the correct file, f.e "Quantity" column, and get f.e value 12 from it, then check the same column in other file, and if it is not 12, then make it 12. Easy. But I cannot find any words about changing a single cell value in their documentation. Can you help me?

I didn't get it, wouldn't it be the most simple thing?

column_name = 'Quantity'
value_to_find = 12
sheets1 = pe.get_book(file_name='Sheet1.xls')
sheets1[0].name_columns_by_row(0)
row = sheets1[0].column[column_name].index(value_to_find)

sheets2 = pe.get_book(file_name='Sheet2.xls')
sheets2[0].name_columns_by_row(0)
if sheets2[0][row, column_name] != value_to_find:
    sheets2[0][row, column_name] = value_to_find

EDIT

Strange, you can only assign values if you use cell_address indexing, must be some bug. Add this function:

def index_to_letter(n):
    alphabet = list('ABCDEFGHIJKLMNOPQRSTUVWXYZ')
    result = []
    while (n > 26):
        result.insert(0, alphabet[(n % 26)])
        n = n // 26
    result.insert(0, alphabet[n])
    return ''.join(result)

And modify the last part:

sheets2[0].name_columns_by_row(0)
col_letter = index_to_letter(sheets2[0].colnames.index(column_name))
cel_address = col_letter+str(row+1)
if sheets2[0][cel_address] != value_to_find:
    sheets2[0][cel_address] = value_to_find

EDIT 2

Looks like you cannot assign only when you use the column name directly, so a around would be to find the column_name's index:

sheets2[0].name_columns_by_row(0)
col_index = sheets2[0].colnames.index(column_name)
if sheets2[0][row, col_index] != value_to_find:
    sheets2[0][row, col_index] = value_to_find