Empty Set in Python

Checking for an Empty Set in Python

In this part, we will be learning about different ways to check for an empty set in Python. We have many built-in functions and operators to check for empty sets in Python.

By Using the “not” Operator

Code:

# Initializing an empty set
sampleSet = {}
 
# Using “not” operator
if not sampleSet:
    print ("The set is empty")
else:
    print ("The set is not empty")

You can also try this code with Online Python Compiler

Run Code

Output:

In the preceding example, we generated an empty set called 'sampleSet'. The “not” operator was then used to reverse the incorrect value.

An empty set in Python always evaluates to false. As a result, if we supply an empty set to the if condition, it will be false. However, the not operator converts the false value to the true value. As a result, the if condition is set to true. And the output was " The set is empty".

By Using len() Function

Code:

# Initializing an empty set
sampleSet = {}
 
# Using “len()” function
Len_sampleSet = len(sampleSet)

# Using if-else Statement
if Len_sampleSet == 0:
    print ("The set is empty")
else:
    print ("The set is not empty")

You can also try this code with Online Python Compiler

Run Code

Output:

You can compile it with online python compiler.

In the preceding example, we first created an empty set called 'sampleSet'. The length of the set was then calculated using the built-in function len() and saved in the variable 'Len_sampleSet'. Then we used an if statement to see if the list length was equal to zero.

If the condition is satisfied, the output is  “The set is empty”. Else we print “The set is not empty".

By Comparing with Another Empty Set

Code:

# Initializing an empty set ‘MySet1’
sampleSet1 = {'Hello', 'World' }

# Initializing an empty set ‘MySet2’
sampleSet2 = {}
 
# Comparing both the sets
if sampleSet1 == sampleSet2:
    print('The set is empty!')
else:
    print('The set is not empty!')

You can also try this code with Online Python Compiler

Run Code

Output:

In the preceding example, we created two sets, “sampleSet1”, and “sampleSet2”. Assume we need to determine whether or not a set 'sampleSet1' is empty. Then we can do so by creating an empty set in Python called 'sampleSet2'. Then, using the decision-making statement, i.e., the if-else condition, compare 'sampleSet1' with 'sampleSet2'. 

If 'sampleSet1' equals 'sampleSet2', that signifies 'MySet1' is an empty set. Otherwise, it is not empty. And by comparing it to another empty set, we can check for an empty set.

Frequently Asked Questions

What distinguishes Python sets?

A set is an unsorted grouping of elements. Every set element must be unique (no duplication) and immutable (cannot be changed). A set, on the other hand, is malleable. We can add and remove items from it.

Can different data types be used in sets?

A set can be of any data type, such as ‘text’, ‘int’, or ‘boolean’.

In Python, are sets immutable?

In Python, set items are immutable (unchangeable), do not duplicate values, and are unordered.

Is a set a type of array?

A set is unordered, and each element in a set can only appear once. While an array can have duplicate elements, each value in a set is distinct. So the set is not an array while it looks like one in some cases.

What is the correct technique to declare an empty set?

To make an empty set in Python, use the set() function with no arguments; if we use empty curly brackets "{ }", we will get an empty dictionary.

Conclusion

In this article, we have discussed the empty set in Python in detail. We saw what it was and then explored different ways to check whether or not the given set was empty.

Recommended Readings:

• Fibonacci Series in Python
• Python List Operations
• Escape Sequence in Python

Check our coding-related articles on the links:

• Balanced Binary Search Trees 
• Rabin Karp Algorithm
• Check if an array represents in order of BST
• The longest common prefix from a suffix array