get the count of elements of tuples of your own…not just the range or sequence

问题

The below code is running for first three elements of the tuple of this list

SS1=[(1, 2, 3, 4, 5), (1, 2, 3, 4, 6), (1, 2, 3, 5, 6), (1, 2, 4, 5, 6), (1, 3, 4, 5, 6), (2, 3, 4, 5, 6)]

from collections import Counter
c = Counter(elem[0:3] for elem in SS1)

for k, v in c.items():
    if (v > 0):
        print(k,v)

and the output is:

(1, 2, 3) 3
(1, 2, 4) 1
(1, 3, 4) 1
(2, 3, 4) 1

But my expectation is not just for first three tuple...i want the counter for tuple (0,2,3) or tuple (1,2,4) likewise i can pass any three position of the tuple and get the count of it... How can I do this?

回答1:

If what i understood from your question is correct, the code below will solve your issue:

SS1=[(1, 2, 3, 4, 5), (1, 2, 3, 4, 6), (1, 2, 3, 5, 6), (1, 2, 4, 5, 6), (1, 3, 4, 5, 6), (2, 3, 4, 5, 6)]

from collections import Counter

def get_new_list(a, pos):
    # Check if any element in pos is > than the length of the tuples
    if any(k >= len(min(SS1, key=lambda x: len(x))) for k in pos):
        return

    for k in a:
        yield tuple(k[j] for j in pos)

def elm_counter(elm):
    if not len(elm):
        return 

    c = Counter(elm)
    for k, v in c.items():
        if v > 0:
            print(k, v)

elm = list(get_new_list(SS1, (0, 2, 4)))
elm_counter(elm)
print('---')
elm = list(get_new_list(SS1, (1, 2, 4)))
elm_counter(elm)

Output:

(1, 3, 5) 1
(1, 3, 6) 2
(1, 4, 6) 2
(2, 4, 6) 1
---
(2, 3, 6) 2
(2, 3, 5) 1
(3, 4, 6) 2
(2, 4, 6) 1

来源：https://stackoverflow.com/questions/44494022/get-the-count-of-elements-of-tuples-of-your-own-not-just-the-range-or-sequence