How to read and write multiple files?

Question

I want to write a program for this: In a folder I have n number of files; first read one file and perform some operation then store result in a separate file. Then

Answer 1

This thing also works for reading multiple files, my file name is fedaralist_1.txt and federalist_2.txt and like this, I have 84 files till fedaralist_84.txt

And I'm reading the files as f.

for file in filename:
        with open(f'federalist_{file}.txt','r') as f:
             f.read()