从Python列表中仅生成某些组合

Question

I have used the following script to generate all combinations:

import itertools
x = 7
my_list = range(1, 11)
for k in [x]:
   for sublist in itertools.combinations(my_list, k):
      print sublist

For the second part I will take 6 random elements from range(1, 11). Let's call them my_second_list. I need to generate the minimum number of combinations of my_list in order to obtain at least one combination to include let's say 5 elements from my_second_list.

Any ideas on how to do that?

Answer 1

import itertools

x = 7
my_list = range(1,11)

for k in [x]: # isn't this just 7?
    your_output = (combination for combination in itertools.combinations(my_list,k) if all(element in combination for element in [1,2,3,4,5]))

It's ugly as heck, but that's how I'd do it (if I'm understanding your question correctly. You're trying to get only those combinations that contain a certain subset of items, right? If you want all combinations BEFORE and INCLUDING that first combination that contains the subset of items, I'd do:

accumulator = list()
subset = [1,2,3,4,5] # or whatever
for k in [x]:
    for combination in itertools.combinations(my_list,k):
        accumulator.append(combination)
        if all(el in combination for el in subset):
            break

Depending on your exact use case you may want to consider defining subset as a set (eg {1,2,3,4,5} ) and do subset.issubset(set(combination)) but it's hard to tell if that's better or not without doing some profiling.