Python | Check if two lists have at-least one element common
Given two lists a, b. Check if two lists have at least one element common in them.
Input : a = [1, 2, 3, 4, 5] b = [5, 6, 7, 8, 9] Output : True Input : a=[1, 2, 3, 4, 5] b=[6, 7, 8, 9] Output : False
Method 1 : Traversal of List
Using traversal in two lists, we can check if there exists one common element at least in them. While traversing two lists if we find one element to be common in them, then we return true. After complete traversal and checking, if no elements are same, then we return false.
Method 2 : Using Set and Property
Using set’s and property, if there exists at least one common element then set(a)&set(b) returns a positive integer, if it does not contains any positive integer, then it returns 0. So we insert a in set_a and b in set_b and then check if set_a & set_b for a positive integer or not.
Method 3 : Using Set Intersection
Using set’s intersection inbuilt function. a_set.intersection(b_set) returns a positive integer if there is at least one element in common, else it returns 0. So we insert a in set_a and b in set_b and then check a_set.intersection(b_set), and returns depending on the value.