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This tutorial will demonstrate different ways to append elements to the front of a list in Python.

Throughout this tutorial, we will use a list of integers as an example to focus on list insertion rather than inserting various data types because the list insertion method should be the same regardless of the data type the list contains.

insert()Adding an element to the front of a list in Python

insert()The function inserts an element into a given index of an existing list. It accepts two parameters, the index to be inserted and the value to be inserted.

insert(idx, value)

For example, we will insert an element into an existing list of size 5. To use this function to append an element to the front of a list, we should set the first argument to 0, which means that the insertion is done at index 0- the beginning of the list.

int_list = [13, 56, 5, 78, 100]

int_list.insert(0, 24)

print(int_list)

Output:

[24, 13, 56, 5, 78, 100]

+Adding an element to the front of a list using the operator in Python

Another way to append elements to the front of a list is to use +the operator. Using the operator on two or more lists +combines them into a specified order.

If you list1 + list2add together, then it will concatenate list2all the elements in list1after the last element of . For example, let's use +the operator to add an integer to an existing list.

to_insert = 56
int_list = [13, 5, 78, 19, 66]

int_list = [to_insert] + int_list

print(int_list)

Note to_insertthat the variable is enclosed in square brackets []. This is done to convert the single integer to a list data type, making list appending possible.

Output:

[56, 13, 5, 78, 19, 66]

Use unpacking to insert elements at the beginning of a list

Unpacking is an operation in Python that allows unique iterable manipulations to be possible. Unpacking allows the developer to distribute iterables more flexibly and efficiently.

Unpacking also allows you to merge elements of an existing iterable, which is what we use in this example to insert elements at the beginning of the list.

To append an element to the beginning of a list using unpacking, we use the unpack operator *to merge a single integer with the existing list, placing the integer at the beginning of the newly formed list.

to_insert = 7
int_list = [19, 22, 40, 1, 78]

int_list = [to_insert, *int_list]

print(int_list)

Output:

[7, 19, 22, 40, 1, 78]

From a performance perspective, using unpacking is the fastest of all solutions. insert()The method comes right after unpacking. Using +the operator is significantly slower than the above two solutions.

If you are inserting at the beginning of a list with a large number of elements, it is better to use unpacking or insert()to speed up the operation.