Hi
Here's a simple solution to your problem. The end goal is to convert all credits to negative numbers:
1. Open a new blank excel workbook and "Save as" -> .csv format (Comma delimited). A .csv file does not store formulae, formatting etc.
2. From your Tally-extracted excel file, copy the sheet with the Dr-Cr formatted columns and paste into the blank .csv file
3. Save and close the .csv file. Now reopen it.
4. You'll see that all the columns in the .csv file with Dr-Cr formats now include Dr and Cr suffixed as a part of the string itself. This is now easy to work with as it can be easily read by any normal excel formula. Formulae otherwise don’t read Cr/Dr when they’re part of the format itself.
5. Copy all the data back from your .csv into a new sheet (say, Sheet 2) in your excel.
6. In sheet 3 of the excel file, apply the following formula for the cells with data (here I'm using cell H5 as an example):
=IF(RIGHT('Sheet 2'!H5,2)="Cr",-'Sheet 1'!H5,'Sheet 1'!H5)
What does this do? From the Sheet 2 that contains your un-formatted data (with Dr/Cr along with the number as string), you are first reading whether that particular cell has "Cr" as the last 2 characters of the string. If it does, you are converting that cell to negative by specifying minus of the corresponding cell from Sheet 1. If there is no "Cr" present in the string, it simply returns the original value as it is from Sheet 1.
This is a pretty simple solution as it gives you the flexibility to do whatever you want with your data once you can see Dr/Cr in the cell value.