How do I add another loop to my nested loop

[greenpine]

thanks for your reply;
sorry again for even more confusion.
I think the second part about saving the last index number in a text file, made it hard to understand, that was my understanding of making the second loop to be done easier.

I edited my post and removed that part from my original post, there is no writing to CSV file or else in process of what I want.
It is just reading rows of data of all CSV files row by row and use data from rows to run the function, then it is done.

I am not sure about reading all rows of all CSV files at once is a good option, I could have over 50 CSV files and each has over 200 rows of data, so I might have a server memory issue or high CPU usage, as I am testing it on pythonanywhere dot come free account, the resource is limited for free accounts.
Thanks again.

[greenpine]

did anyone come to a solution to this code?
I appreciate it.