# intersection_update() in Python to find common elements in n arrays

In this article, we will learn about the iintersection_update() in Python to find out common elements in n arrays.

The problem is that we are given an array containing lists, find all common elements in given arrays?

## Algorithm

1.Initializingres with the first list inside the array
2.Iterating through the array containing lists
3.Updating the res list by applying intersection_update() function to check the common elements.
4.Finally returning the list and display the output by the help of the print statement.

Now let’s take a look at its implementation

## Example

def commonEle(arr):

# initialize res with set(arr)
res = set(arr)

# new value will get updated each time function is executed
for curr in arr[1:]: # slicing
res.intersection_update(curr)
return list(res)

# Driver code
if __name__ == "__main__":
nest_list=[['t','u','o','r','i','a','l'], ['p','o','i','n','t'], ['t','u','o','r','i','a','l'],       ['p','y','t','h','o','n']]
out = commonEle(nest_list)
if len(out) > 0:
print (out)
else:
print ('No Common Elements')



## Output

['o', 't']

## Conclusion

In this article, we learned about the iintersection_update() in Python to find common elements in n arrays and its implementation.