How to find common elements in list of lists?
comparison, list, python, recursion
Solution
You are looking for the set intersection of all the sublists, and the data type you should use for set operations is a set:
result = set(p[0])
for s in p[1:]:
result.intersection_update(s)
print result
Problem
I'm trying to figure out how to compare an n number of lists to find the common elements. For example: ``` p=[ [1,2,3], [1,9,9], .. .. [1,2,4] >> print common(p) >> [1] ``` Now if I know the number of elements I can do comparions like: ``` for a in b: for c in d: for x in y: ... ``` but that wont work if I don't know how many elements p has. I've looked at this solution that compares two lists https://stackoverflow.com/a/1388864/1320800 but after spending 4 hrs trying to figure a way to make that recursive, a solution still eludes me so any help would be highly appreciated!