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# Python Set Function

Last Updated on February 28, 2023 by Prepbytes Python is a popular programming language that offers a wide range of built-in functions to simplify and streamline the coding process. Each of the built-in functions has its own applications where they can prove to be useful. One such function is the "set" function, which creates a set object in Python. In this article, we will explore the set function in detail and discuss its various features, properties, and use cases.

## Python Set() Function

Python set function can be understood as an unordered collection of unique elements. It is similar to a list or a tuple, but it does not allow duplicate values. This means that every element in a set must be unique. Sets are mutable, which means that you can add, remove, or modify their elements.

You can create a set in Python by two methods one of them is by enclosing a comma-separated list of elements within curly braces {} and one is by putting them inside the set variable.

### Syntax of Python Set Function

The python set function has two syntaxes that are given below:

``my_set={val1, val2, val3, .......}``

or

``my_set= set(iterable)``

Note:

• We are able to include different types of numbers inside the groups.
• We must give values in the second style as iterable objects, collections, or sequences, such as lists, tuples, strings, sets, dictionaries, etc.
• An empty dictionary is made in the first syntax’s place of the empty set if the parameter is left unfilled.

### Parameters of Python Set Function

In Python, a set is created using the set() method. Python’s set function only needs one argument. It is a parameter with values that can be optionally added to the collection. A collection(set, dictionary), or iterator object should be used as the input values.

### Return Values of Python Set Function

The set() method in Python uses the iterable values passed as a parameter to build and output a set. The set() method gives an empty set if we do not pass any parameters into it.

## Examples of Python Set Function

Now, we will understand the python set function with the help of various examples.

Example 1 of Python Set Function: Creating a Set
To create a set in Python, you can use curly brackets {} or the built-in set() function. Below is the code implementation and output of the same.

Code Implementation:

```my_set = {1, 2, 3}
my_set2 = set([4, 5, 6])
print(my_set)
print(my_set2)```

Output

``````set([1, 2, 3])
set([4, 5, 6])``````

Explanation of the above code
In the above example we have created two sets by following both of the syntaxes and by printing we are getting the elements that have been inserted in the set.

Example 2 of Python Set Function: Adding Elements to a Set
To add an element to a set, you can use the add() method. The code implementation and output of the above-mentioned example are given below:

Code Implementation

```my_set = {1, 2, 3, 4}
print(my_set)```

Output

``set([1, 2, 3, 4, 5])``

Explanation of the above example
Here we have already created a set and now we have added an extra element using add function in the same set.
Note that if you try to add an element that already exists in the set, it won’t be added again.

Example 3 of Python Set Function: Removing Elements from a Set
To remove an element from a set, you can use the remove() method. The code implementation of the above-mentioned example is shown below:

Code Implementation

```my_set = {1, 2, 3}
my_set.remove(1)
print(my_set)```

Output

``set([2, 3])``

Explanation of the above code
To remove an element from an already existing set we have to pass the value of the element to be deleted like in the above example we have passed 2.
Note that if you try to remove an element that doesn’t exist in the set, you will get a KeyError.

Example 4 of Python Set Function: Union of Sets
To get the union of two sets, you can use the union() method or the "|" operator. The Code and output of the above-mentioned example are given below:

Code Implementation

```set1 = {1, 2, 3, 4}
set2 = {3, 4, 5, 6}
set3 = set1.union(set2)
set4 = set1 | set2
print(set3)
print(set4)```

Output

``````set([1, 2, 3, 4, 5, 6])
set([1, 2, 3, 4, 5, 6])``````

Explanation of the above example
In the above example, we are finding the total elements in both the sets without repetition or union by both the methods explained above.

Example 5 of Python Set Function: Intersection of Sets
To get the intersection of two sets, you can use the intersection() method or the "&" operator. The implementation and output are given below:

Code Implementation

```set1 = {1, 2, 3, 4}
set2 = {3, 4, 5, 6}
set3 = set1.intersection(set2)
set4 = set1 & set2
print(set3)
print(set4)```

Output

``````set([3, 4])
set([3, 4])``````

Explanation of the above example
In the above example, we have used two methods to find the intersections of the two sets.

Example 6 of Python Set Function: Difference of Sets
To get the difference between two sets, you can use the difference() method or the "-" operator. Below is the code and implementation of the above-mentioned example.

Code Implementation

Output

``````set([1, 2])
set([1, 2])
set([1, 2])``````

Explanation of the above code
In the above example, we are finding the difference between two sets using the above explained two methods.

## Properties of Python Set Function

Sets in Python have several properties that make them a useful data structure for various applications. Some of the properties of sets in Python are:

• Unordered: Sets in Python are unordered, which means that the elements are not stored in any particular order. This allows for efficient operations like membership testing, union, intersection, and difference.
• Unique elements: Sets in Python only contain unique elements. This makes sets useful for finding unique elements in a collection or removing duplicates.
• Immutable elements: Elements in a set must be immutable, meaning they cannot be changed once they are added to the set. This ensures that the set remains consistent and avoids potential errors due to changing elements.
• Mutable set: A set is mutable, meaning that you can add or remove elements from a set after it is created.
• Efficient operations: Sets in Python are optimized for efficient operations like membership testing, union, intersection, and difference. These operations can be performed on large sets in a matter of milliseconds, making sets a useful tool for many applications.

Conclusion
The set function in Python provides a powerful way to work with sets, which are important data types in computer science and mathematics. Sets offer a simple and efficient way to store and manipulate collections of unique elements, and Python’s built-in set functions make it easy to perform a wide range of set operations. By mastering the set function and its associated methods, you can take full advantage of Python’s capabilities and become a more efficient and effective programmer.

1. How do you get the length of a set in Python?
You can get the length of a set in Python using the built-in len() function.

2. How do you check if an element is in a set in Python?
You can check if an element is in a set in Python using the in keyword.

3. How do you get the symmetric difference between two sets in Python?
You can get the symmetric difference of two sets in Python using the symmetric_difference() method or the ^ operator.

4. How do you check if a set is a subset of another set in Python?
You can check if a set is a subset of another set in Python using the issubset() method.

5. How do you create an empty set in Python?
You can create an empty set in Python using the set() function, without any arguments.