Python data entry into excel based on equality check with dataframe

Question

My objective is to enter/type in values into Excel cells if the column names and indices match between Excel and dataframe.

So, my code does the below

1. Gets the ID values from the dataframe

2. for each ID, see whether it is present in excel file

3. If they are present, get the column name list for those corresponding IDs (from dataframe)

4. Filter only non-NA columns

5. Check whether those columns names are present in excel file

6. If both ID and column names (between dataframe and excel) match, key in the column value (from dataframe) into the excel sheet at appropriate position

You can refer this post for more details on the problem.

My code looks like below:

sales = xlwings.book('file1.xlsx')
df_value = region_1['ID'].tolist()
for val in df_value:
    for a_cell in sales.sheets[0]['B5:B8']:
        if a_cell.value == val:
            rn1 = a_cell.row
            temp = region_1.loc[[val]]
            temp = temp.dropna(axis=1, how='all')
            colu = temp.columns.tolist()
            for col in colu:
                for b_cell in sales.sheets[0]['G3:J3']:
                    if b_cell.value == col:
                        rn2 = b_cell.row
                        data_entry_loc = str(b_cell.address[1]) + str(rn1)
                        enter_val = temp[col].values
                        sales.sheets[0][data_entry_loc].value = enter_val

However, am not sure whether this code is elegant and efficient enough to handle big data. While it worked for sample data provided in the above post, I would like to seek your opinion/suggestions on how it can be improved. You can please write the improved version of the code as an answer below.

In case, if you wish to try out the sample data, you can find below

Sample dataframe

ID,DIV,APP1,APP2,APP3,Col1,Col4
1,A,AB1,ABC1,ABCD1,20,40
2,A,AB1,ABC2,ABCD2,60,
3,B,BC1,BCD1,BCDE1,10,20

region_1 = pd.read_clipboard(sep=',') 
region_1.set_index(['ID','DIV','APP1','APP2','APP3'],inplace=True)

Input excel file

I expect my output to be like as shown below