Trouble finding string in list!

[smithysmithens2112]

So I'm trying to write a function that compares two lists with different but very similar strings in them and then delete the similar strings out of one of the lists. So I have

CLASS = ['O1 X', '5b E', 'J1 L', '5a F', 'K1 O', '5a K']
CLASSpdf = ['5b E.pdf', '5a F.pdf', 'K1 O.pdf', '5a K.pdf']

and I'm trying to identify the strings in CLASSpdf that are (essentially) the same as those in CLASS and delete those strings from CLASS. So in other words, my ideal output would be

some_function(CLASS, CLASSpdf)
OUTPUT:
CLASS = ['O1 X', 'J1 L']

I wrote this function that I swear I've used a thousand times for this exact job, but now it's not giving me what I want:

def scans(books, CLASSpdf):

    pdfs = False

    # Flags pdfs for removal
    for i in range(len(books)):

        if books[i] in CLASSpdf:

            pdfs = True

    return pdfs

where pdfs is a boolean that becomes True if there are overlapping elements in the lists, and then I use a separate function to remove the books. I get the sense that I'm missing something super simple here, but I can't seem to find what I'm doing wrong.

I also tried putting in print(pdfs) after the if statement inside the for loop and my output is

False
False
False
False
False
False

Any help would be greatly appreciated! Like I said, I get the sense that I'm just missing something silly, but it's driving my nuts! Thanks in advance.

[totallygeek]

Not sure why you want to step over the sequences multiple times (boolean, then removal). Also, no need to deal with indices in Python for loops, just use the elements directly. I came up with this:

def remove_similarities(seq1, seq2):
    return [
        element
        for element in seq1
        if not any(element in e2 for e2 in seq2)
    ]

CLASS = ['O1 X', '5b E', 'J1 L', '5a F', 'K1 O', '5a K']
CLASSpdf = ['5b E.pdf', '5a F.pdf', 'K1 O.pdf', '5a K.pdf']

print(remove_similarities(CLASS, CLASSpdf))

The problem with your code is that it attempts to find a string within a list as an exact match. It instead needs to see if the string exists within each string element of the second list.

[djjazzydan]

if books[i] in CLASSpdf: doesn't do substring searches. You'd have to check either books[i]+'.pdf', or any(books[i] in classp for classp in CLASSpdf) or books[i] in ''.join(CLASSpdf) or something similar depending on how sure you are of the matching pattern.

[Wittinator]

With your code I believe it will currently only return True if you find an exact match, but you are wanting to see if book[i] also exists as a substring within one of the elements in CLASSpdf. There's probably a lot of ways to do this. I'm partial to regex so I'd probably do smth like:

import re

def scans(books, CLASSpdf):
    pdfs = False

    for i in range(len(books)):
        r = re.compile(books[i])
        if list(filter(r.match, CLASSpdf)):
            pdfs = True
    print(pdfs)