how to append all the commonelements two lists have in python code example

Example 1: find common words in two lists python

list1 = ['little','blue','widget']
list2 = ['there','is','a','little','blue','cup','on','the','table']

list3 = set(list1)&set(list2)

list4 = sorted(list3, key = lambda k : list1.index(k))

Example 2: python common elements in two arrays

# using numpy
import numpy as np
a = np.array([1,2,3,2,3,4,3,4,5,6])
b = np.array([7,2,10,2,7,4,9,4,9,8])
# using intersect1d
print(np.intersect1d(a,b))
# output
# [2 4]

Example 3: same elements of two sets in python

x = {2, 3, 5, 6}
y = {1, 2, 3, 4}

z = x.intersection(y)