CODEWITHSUNDEEP
python
Walter
Walter

Reputation: 323

Delete lines in files A and B that exist in file A

i am having a problem. I have a blacklist.txt file that contains 5 links

Link1.com
Link2.com
Link3.com
Weirdlink4.com
Fivelink5.com

I also have a Links.txt which contains all these 5 links and 40 more. I am trying to make a script that can read what blacklist.txt contains and remove those links from Links.txt and removing the links aswell in blacklist.txt.

with open("Blacklist.txt", "w+") as blacklist:
    with open("Links.txt", "w+") as links:
        blackinfo = blacklist.read()
        linksinfo = links.read()
        for i in blackinfo:
            if i in linksinfo:

At this point i am completely confused as to how i am going to delete the link from both files because i is holding the value. Thanks in advance

Upvotes: 0

Views: 59

Answers (1)

TheoretiCAL
TheoretiCAL

Reputation: 20561

Using list comprehensions you can create a new list of links that you override your link files with:

with open("Blacklist.txt", "r+") as blacklist_file :
    with open("Links.txt", "r+") as links_file :

        bl_links = blacklist_file.read().splitlines()
        blacklist_file.seek(0) #reset file handle's position to start of file for writing

        links = links_file.read().splitlines()
        links_file.seek(0)

        # Only keep blacklist links that did not exist in links
        new_blacklist_links = [link for link in bl_links if link not in links]

        # Only keep links that did not exist in the blacklist
        new_links = [link for link in links if link not in bl_links]

        blacklist_file.write('\n'.join(new_blacklist_links))
        blacklist_file.truncate() #truncate the file to what we have just written

        links_file.write('\n'.join(new_links))
        links_file.truncate()

Upvotes: 2

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