How to Convert Set to List in Python

Type conversion, also known as type casting or type coercion, is the process of changing the data type of a variable or value from one type to another. In programming, different data types have different representations and behaviors, and type conversion allows you to manipulate and combine values of different types.

In this tutorial, we will discuss the various methods and techniques that you can use to convert a python set into a python list.

What is a Python Set?

In Python, a set is an unordered collection of unique elements. It is defined by enclosing a comma-separated list of items inside curly braces {}.

The example below demonstrates how to create a simple set in Python:

set_var = {1, 2, 3, 4, 5}

In this example, set_var is a set that contains the integers from 1 to 5.

Note that sets do not allow duplicate elements, so if you try to add duplicate values, they will be automatically eliminated:

set_var = {1, 2, 2, 3, 3, 4, 5, 5}
print(set_var)

Output:

{1, 2, 3, 4, 5}

You can also create an empty set using the set() constructor:

empty_set = set()

Sets in Python provide various operations and methods for manipulation, such as adding and removing elements, performing set operations like union, intersection, and difference, checking membership, and more.

The following are some basic set operations you can perform in Python.

Add Element to Set

To add an element to a Python set, you can use the add() method as:

set_var.add(6)

This should add the specified element to the existing set.

Remove Element From Set

Similarly, you can use the remove() method to delete an element from a set. An example is as shown:

set_var.remove(3)

Union Set

The following example demonstrates how to perform a union set in Python:

set_var = {1,2,3}
set_one = {4, 5, 6, 7}
union_set = set_var.union(set_one)

Output:

{1, 2, 3, 4, 5, 6, 7}

Sets are particularly useful when you need to store a collection of unique elements and perform operations on them efficiently, such as removing duplicates from a list or checking for membership.

What are Python Lists?

In Python, a list is an ordered collection of elements. It is one of the built-in data types and is defined by enclosing a comma-separated list of items inside square brackets []. Here’s an example of creating a list in Python:

list_var = [1, 2, 3, 4, 5]

In this example, list_var is a list that contains the integers from 1 to 5. Lists can hold elements of different data types, and you can even mix different data types within the same list:

mixed_list = [1, 'apple', True, 3.14]

Lists in Python are mutable, which means you can modify them by adding, removing, or changing elements.

Python Convert Set to List

To convert a set to a list in Python, you can use various methods. The following examples demonstrates the various techniques you can use.

Using the List Function

The first and most common method of converting a set to a list is by using the built-in list function. An example is as shown:

set_var = {1, 2, 3, 4, 5}
list_var = list(my_set)
print(list_var)

Output:

[1,2,3,4,5]

Using list comprehension

The second method we can use to convert a set to a list is using list comprehension.

List comprehension is a concise method of creating new lists in Python. It allows you to define a new list based on an existing list (or other iterable) by applying an expression or transformation to each element and optionally applying filters to select specific elements.

The following example demonstrates how to use list comprehensions to convert a set to a list.

set_var = {1, 2, 3, 4, 5}
list_var = [x for x in set_var]
print(list_var)

Output:

[1, 2, 3, 4, 5]

Using the extend() method

You can also use the extend method to convert a set to a list as demonstrated below:

set_var = {1, 2, 3, 4, 5}
list_var = []
list_var.extend(set_var)
print(list_var)

Using the * operator

set_var = {1, 2, 3, 4, 5}
list_var = [*set_var]
print(list_var)

Using the list() constructor with set as an argument

set_var = {1, 2, 3, 4, 5}
list_var = list(set(set_var))
print(list_var)

Conclusion

The above methods illustrated demonstrates how to convert a set to a Python list using built-in features and techniques.