python find common elements in two lists 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: find number of common element in two python array

len([x for x in list1 if x in list2])

Example 3: 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 4: Write a Python program to find common element(s) in a given nested lists.

>>> p = [[1,2,3], [1,9,9], [1,2,4]]
>>> set.intersection(*map(set, p))
set([1])
>>> ip = iter(p)
>>> s = set(next(ip))
>>> s.intersection(*ip)
set([1])