Check whether an item in a list exist in another list or not python

Question

There are 2 list

a= [1,2,3]
b = [1,2,3]

Now I want to check whether an element from a exist in b or not in pytho

Answer 1

I think you should use sets. This is the way you can do it:

def check_element(a, b):
  return not set(a).isdisjoint(b)

Answer 2

bool(set(a)&set(b)) converts a and b into sets and then applies the intersection operator (&) on them. Then bool is applied on the resulting set, which returns False if the set is empty (no element is common), otherwise True (the set is non-empty and has the common element(s)).

Without using sets: any(True for x in a if x in b). any() returns True if any one of the elements is true, otherwise False.

Answer 3

len(set(a+b)) < len(set(a)) + len(set(b))