匹配顺序无关紧要的集合中的确切元素

Question

I'm new to python and I'm trying to match the exact elements between two sets, regardless of order. So if my 2 sets are:

reflist = [1],[2,3,4],[5,6]
qlist = [1,2,3,4],[6,5]

The number of matches should be 1, which is 5,6

I tried to write the following loop to match the elements in qlist against reflist, and count the number of matches:

i = 0
count = 0
for each in qlist:
    while i < len(qlist):
        if each.split(",").sort == reflist[i].split(",").sort:
            count = count + 1
        i = i + 1
print count

However, I keep getting count = 0, even if the order of 5 and 6 in qlist is 5,6. Would really appreciate any help with this!

Answer 1

This could do:

If you have no duplicates:

matches = [x for x in map(set, reflist) if x in map(set, qlist)]

If you have duplicates:

matches = [x for x in map(sorted, reflist) if x in map(sorted, qlist)]

Answer 2

If there are no duplicates in your "sets", convert your "sets" to a set of frozenset s, and find the set intersection -

i = set(map(frozenset, reflist))
j = map(frozenset, qlist)

len(i.intersection(j))
1

Answer 3

You could always use collections.Counter() for this:

from collections import Counter

reflist = [[1],[2,3,4],[5,6]]
qlist = [[1,2,3,4],[6,5]]

result = [list(x.keys()) for x in [Counter(y) for y in reflist] if x in [Counter(y) for y in qlist]]

print(result)

Which Outputs:

[[5,6]]

Answer 4

Here is my one-liner, using frozenset s and and :

len(set(map(frozenset, qlist)) and set(map(frozenset, reflist)))

I understand you are new to Python, hence I will answer your question using your own method, just for the sake of recording the basic straightforward answer for future reference.

First of all, your code shouldn't run at all. It must error out, because both each and reflist[i] are lists, and you are applying a string method of split(",") on them. Therefore you are getting the initial value of count = 0 . You must check in the first place whether your code is even touching all the elements of qlist and reflist . This is not Code Review , hence I will leave it to you to run this and see the answer:

i = 0
count = 0
for each in qlist:
    while i < len(qlist):
        print i
        print each
        print reflist[i]
        i = i + 1

Keep in mind: You don't have to iterate on index! You can just loop over the elements of iterables directly! This is the answer you are looking for:

match = [] # Optional, to see all the matching elements
count = 0 
for q in qlist:
    for r in reflist:
        if set(q) == set(r):
            print q, r
            match.append(q)
            count += 1 
print match
print count, len(match)