How to Add List to Set in Python

Published Jul 18, 2022

We have several ways of adding the elements of a list to a set in Python.

Suppose we want to add the elements of curr_list into curr_set to create a set of { 1, 2, 3 }.

curr_set = set(1)
curr_list = [2, 3]

Quick caveat: if we want to add the entire list as a single element to the set, we’ll have to first convert it to a tuple.

curr_set.add(tuple(curr_list)) # { 1, (2, 3) }

To add all the list elements to a set, we have multiple options.

1. Using update()

We can add all elements from a list using update().

curr_set.update(curr_list)

2. Using the set union operator (|)

The update() method applies the | operator under the hood.

curr_set |= set(curr_list)

3. Using union()

We can also use union() to add a list to a set.

curr_set.union(curr_list)