Question

I have two text file.

file1.txt has:

gedit
google chrome
git
vim
foo
bar

file2.txt has:

firefox
svn
foo
vim

How do I write a script that when executed (with file1.txt and file2.txt as argument) checks for duplication of text in each line (I mean it should process line wise), deletes the duplicated text in both the files.

So after the processing, both file1.txt and file2.txt should have following contents:

gedit
google chrome
git
bar
firefox
svn

Notice that foo and vim has been removed from both files.

Any guidance?

Answer 1

with open('file1.txt','r+') as f1 ,open('file2.txt','r+') as f2:
    file1=set(x.strip() for x in f1 if x.strip())
    file2=set(x.strip() for x in f2 if x.strip())
    newfile=file1.symmetric_difference(file2) #symmetric difference removes those values which are present in both sets, and returns a new set.
    f2.truncate(0) #truncate the file to 0 bytes
    f1.truncate(0)
    f2.seek(0) # to push the cursor back to the starting pointing in the file.
    f1.seek(0)
    for x in newfile:
        f1.write(x+'\n')
        f2.write(x+'\n')

now both files contains:

svn
git
firefox
gedit
google chrome
bar