Concatenate Two Lists in Python Using Iterable Unpacking * Operator

In this blog, we will explain a Python program to concatenate two lists using iterable unpacking * operator. We will explore a code example that shows how this operator can effortlessly add two lists into a single list. By understanding the logic and step-by-step operations of the code, you will gain a solid understanding of this short and efficient concatenation technique.

Lists are fundamental data structures in Python that allow us to store and manage collections of elements. Oftentimes, we may need to combine or concatenate two lists to create a single, unified list. Python provides various techniques for achieving list concatenation, and one of the powerful methods involves using the iterable unpacking * operator.

Let’s dive in and learn how to concatenate two lists in Python using the iterable unpacking * operator.

Python Program to Concatenate Two Lists Using Iterable Unpacking * Operator

# Python Program to Concatenate Two Lists Using Iterable Unpacking * Operator

list_1 = [1, 'a']
list_2 = range(2, 5)

#* operator allows unpacking inside the list or tuple.
list_joined = [*list_1, *list_2]
print(list_joined)

Defining the two lists to be concatenated

In this step, we have two lists: list_1 containing the elements [1, ‘a’] and list_2 containing the elements [2, 3, 4] generated using the range function.

Concatenate the lists using the iterable unpacking * operator

The * operator allows us to unpack the elements from list_1 and list_2 and concatenate them into a new list called list_joined. The resulting list will contain the elements from list_1 followed by the elements from list_2. In this case, list_joined will be [1, ‘a’, 2, 3, 4].

Print the concatenated list

In this step, we simply print the concatenated list using the print function. The output will be [1, ‘a’, 2, 3, 4].

Output:

The output shows the resulting list after concatenating list_1 and list_2. The elements from list_1 (which are [1, ‘a’]) are followed by the elements from list_2 (which are [2, 3, 4]), resulting in the final list [1, ‘a’, 2, 3, 4].

[1, 'a', 2, 3, 4]

Alternative Methods to Concatenate Two Lists in Python

Let’s briefly look at the alternative methods:

Using + Operator:

The + operator can be used to concatenate two or more lists. By simply using the + operator between the lists, you can combine them into a single list. This method is straightforward, concise, and widely understood. It creates a new list without modifying the original lists, which can be desirable in many cases.

Using Unique Values:

You can create a new list by merging the unique values from multiple lists. You can use the set() function to remove duplicate values and then convert it back to a list. However, this method may change the order of elements and is more suitable for situations where uniqueness is the primary concern.

Using Extend():

The extend() method can be used to append elements from one list to another. By calling extend() on the first list and passing the second list as an argument, you can add the elements of the second list to the first list. This method modifies the original list in place, unlike the + operator, which creates a new list.

In this tutorial, we used the * Operator as it provides a compact syntax for combining lists, resulting in cleaner and more readable code. By unpacking the elements of the lists, the * operator eliminates the need to create a new list object, making it a more memory-efficient approach, especially for larger lists. It can be used not only for concatenating lists but also for unpacking elements in other contexts, such as function calls or list comprehension, enhancing its versatility.

Conclusion

In this tutorial, the code showcases a concise and efficient way to concatenate two lists using the iterable unpacking * operator in Python. By unpacking the elements of the lists and combining them into a new list, we can effortlessly merge the contents of multiple lists.

This technique is particularly useful when dealing with large datasets or when combining lists of different types. It enhances code readability and reduces the complexity of list concatenation, making it a valuable tool in Python programming.

By understanding and utilizing the iterable unpacking * operator, Python developers can efficiently concatenate lists and streamline their code. It is an essential technique to have in your programming toolkit when working with list manipulation and data aggregation tasks.

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