Equivalent of =INDEX(....MATCH()) in python

Question

I am using Python and Excel at the same time. I am looking up at a Excel sheet using xlwings , this sheet has the following values:

date        rate
31/01/2016  0.60%
29/02/2016  0.60%
31/03/2016  0.60%
30/04/2016  0.60%
31/05/2016  0.60%
30/06/2016  0.60%
31/07/2016  0.60%
31/08/2016  0.60%
30/09/2016  0.60%
31/10/2016  0.40%
30/11/2016  0.40%
....
31/07/2030  1.65%

Then I have a dataframe that looks exactly like that as well, but it has different rates. What I want to do is to make python compare the values Excel-DataFrame based on the dates and paste the dataframe values in the Excel sheet

So far, I know how to grab such values in Excel using sht_in.range(start,end).value and how to insert them into the Excel sheet using sht_in.range(start,end).value = df_data , but I am not quite sure how to do the next steps

Answer 1

What you want to do is to read the range from Excel into a dataframe by

xl_df = pd.DataFrame(in_sht.range('A2:B10').value)

Depending on the existing dataframe that you want to compare values to, you may need to rename the columns of this dataframe.

Then you will probably need to perfrom a left join on the Excel-datafram with the Python-dataframe.

new_df = xl_df.merge(py_df, on=0, how='left').drop(columns=['1_x'])

The code above merges by the first column in each dataframe and drops the percentage-values from the xl_df (the x-dataset). You should consider merging the columns by column name instead.

You can then override the data in excel with the new dataframe by

sht_in.range('A2').value = new_df.values.tolist()