Multiple Files Comparing Using Python

I have 5 files as follows F1: ABL1 ABR AHSG AIRE CCKBR LRBA CDC27 CENPA F2: AKT1 APC APP AR CCND1 C11ORF2 CCNE1 CST6 CTNNB1 DBI DEFA1 DNMT1 EEF1A1 EEF1G F3: ACTG1 AMPH A

Solution 1:

It's much easier (I didn't do any error checking when opening the files, though):

filenames = ["F1.txt", "F2.txt", "F3.txt", "F4.txt", "F5.txt"]
files = [open(name) for name in filenames]
sets = [set(line.strip() for line in file) 
            for file in files]
common = set.intersection(*sets)
for file in files: file.close()