In this tutorial, we will look at how to check if a set is empty or not in Python with the help of some examples.

## How to check if a set is empty?

A set is said to be empty if it does not contain any elements. You can use the following methods to check if a set is empty or not in Python.

- Comparing the length of the set with zero.
- Comparing the set with an empty set.
- Using the set in a boolean context.

Let’s now take a look at each of the above methods with the help of some examples.

### Using the `len()`

function

The length of an empty set is zero.

You can use the Python `len()`

function to calculate the length of the set and then compare it with zero to check if the set is empty or not. Here’s an example –

# create two sets - s1 is empty and s2 is non-empty s1 = set() s2 = {1, 2, 3} # check if set is empty print(len(s1)==0) print(len(s2)==0)

Output:

True False

We get `True`

as the output for the set `s1`

as it is empty and `False`

for the set `s2`

because it’s not empty (has non-zero length).

### Comparing the set with an empty set

You can also check if a set is empty or not by comparing it with an empty set using the `==`

operator. Let’s look at an example.

# create two sets - s1 is empty and s2 is non-empty s1 = set() s2 = {1, 2, 3} # check if set is empty print(s1 == set()) print(s2 == set())

Output:

True False

We get the same results as above.

Note that using curly braces without any elements, `{}`

represents an empty dictionary and not an empty set. Thus, we’re using `set()`

to represent an empty set.

### Using set in a boolean context

If you use a set in a boolean context, it will evaluate to `True`

if it has any elements and it will evaluate to `False`

if the set is empty. Thus, you can use the expression `not s`

to check if the set `s`

is empty or not.

Here’s an example.

# create two sets - s1 is empty and s2 is non-empty s1 = set() s2 = {1, 2, 3} # check if set is empty print(not s1) print(not s2)

Output:

True False

We get the same result as above. `True`

for the set `s1`

as it’s empty and `False`

for the set `s2`

as it’s not empty (`s2`

has three elements).

In this tutorial, we looked at three methods to check if a set is empty or not. Use the method that you are the most comfortable with. Using the `len()`

function to check if a set is empty may be more explicit but it’s very intuitive and is consistent with the mathematical definition of an empty set.

You might also be interested in –

- Python – Check If a List is Empty – With Examples
- Check If a Set Contains an Element in Python
- Add items to a Set in Python

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