loop through list with do something

[Gribouillis]

If the items in mylist are hashable, you could use functools.lru_cache

from functools import lru_cache
import itertools as itt

def myfunct(a):
    #do something with a
    #return something
    print('myfunct({})'.format(a))

myf = lru_cache()(myfunct)
 
mylist = [1,2,3,4,5]

for x, y in itt.combinations(mylist, 2):
    val = myf(x)
    print(x, y)
myf.cache_clear()

Output:
myfunct(1)
1 2
1 3
1 4
1 5
myfunct(2)
2 3
2 4
2 5
myfunct(3)
3 4
3 5
myfunct(4)
4 5