Check for an empty Set in Python

This post will discuss how to check for an empty set in Python.

Python 3.x introduced the syntax for set literals – curly brackets surrounding the contents of a mutable set. However, there is no literal for an empty set in Python. This is because the set literals are distinguished from dictionaries by the absence of key-value pairs (separated by colons). Therefore, {} syntax represents an empty dictionary while set() represents an empty set.

1. Using `len()` function

A simple solution to check if a set is empty is using the len() function. It returns the total number of items in a set. Since an empty set has a length of 0, you can use this as:

if __name__ == '__main__':

s = set()

isEmpty = (len(s) == 0)

if isEmpty:

print("Set is empty")

else:

print("Set is not empty")

Download Run Code

2. Using `==` operator

Another preferred explicit way to check for an empty set is to compare the set with an empty set set() using the == operator. The following example demonstrates this:

if __name__ == '__main__':

s = set()

isEmpty = (s == set())

if isEmpty:

print("Set is empty")

else:

print("Set is not empty")

Download Run Code

3. Checking for an empty set in boolean contexts

Finally, if you need to check if a set is empty in boolean contexts, you can use the following code:

if __name__ == '__main__':

s = set()

if len(s):

print("Set is not empty")

else:

print("Set is empty")

Download Run Code

You can even skip the comparison. This works since an empty set is interpreted as False in a boolean context in Python.

if __name__ == '__main__':

s = set()

if s:

print("Set is not empty")

else:

print("Set is empty")

Download Run Code

That’s all about checking for an empty Set in Python.

Check for an empty Set in Python

1. Using len() function

2. Using == operator

3. Checking for an empty set in boolean contexts

Share this:

1. Using `len()` function

2. Using `==` operator