python: Searching strings in one list in another list, then appending an entire list entry to a new list

Question

Example:

L1=['cat', 'dog', 'fish', 'bird', 'rabbit', 'horse']

L2=[('cat', 'a', 'b', 'c'), ('cat', 'c', 'd', 'e'), ('cat', 'e', 'f', 'g'), ('fish', 'x', 'y', 'z'), ('dog', 'w', 'x', 'y'), ('dog', 'z', 'y', 'x'), ('horse', '1', '2', '3'), ('monkey', 'a', 'b', 'c'), ('kitten', 'h', 'i', 'j'), ('bird', '4', '5', '6')]

I am trying to search the strings in L1 in L2, so that if the string in L1 is present in any part of L2, the whole entry from L2 "('cat, a, b, c')" is appended to a new list. I also thought that maybe removing the entries that do not have any part of a string from L1 would work. I tried:

def searcher(L1, L2):
    common = []
    for x in L1:
        if re.search(x, L2):
            common.append(L2)

    return common

but that didnt work. The actual list I am using is much longer, so an efficient code would really help me out.

Thanks!

Why the parentheses around the string in `L2`? They don't do anything. — Sven Marnach, Jan 24 '11 at 18:08
Or do you actually mean `('cat', 'a', 'b', 'c')` for the first entry of L2? — Sven Marnach, Jan 24 '11 at 18:09
@marsx: What have you tried that doesn't work? Otherwise this is just a homework question. — user225312, Jan 24 '11 at 18:16
I tried: def searcher(L1, L2): common = [] for x in L1: if re.search(x, L2): common.append(L2) return common — marsx, Jan 24 '11 at 18:23
If `L1 = ('pig', 'cat')` and `L2 = [('a, pig, jump'), ...]`, should `common` include `('a', 'pig', 'jump')`? — Paul Fisher, Jan 24 '11 at 18:32
ya that's the idea, it should include all of the entries from L2 that I posted except the kitten and monkey ones — marsx, Jan 24 '11 at 18:35

Sven Marnach · Accepted Answer · 2011-01-24T18:41:07.067

5

Try

s = set(L1)
new_list = [a for a in L2 if any(b in s for b in a)]

edited Jan 24 '11 at 18:41

answered Jan 24 '11 at 18:06

Sven Marnach

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@marsx: The solution was for the first version of your question. Updated now. – Sven Marnach Jan 24 '11 at 18:41
actually, this works perfectly once you take out the .split part. Thanks! – marsx Jan 24 '11 at 18:42

score 0 · Answer 2 · answered Jan 24 '11 at 18:17

0

Maybe

s = set(L1)
new_list = [a for a in L2 if s.intersection([w.strip() for w in set(a.split(","))])]

answered Jan 24 '11 at 18:17

Qnan

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python: Searching strings in one list in another list, then appending an entire list entry to a new list

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