Update List in Python

In Python Programming, a list is a sequence of a data structure that is mutable. This means that the elements of a list can be modified to add, delete, or update the values. In this article we will explore various ways to update the list.

Let us see a simple example of updating a list in Python.

a = [1, 2, 3, 4, 5]
print(a)

a[2] = 100
print(a)

[1, 2, 3, 4, 5]
[1, 2, 100, 4, 5]

Explanation

• In the above example, the third element of the list is updated from 3 to 100 using the list indexing method.

Let us now see more ways to update a list in Python.

Appending an Element

Updating a list can also mean to add new elements to the list. The append() method is used to add elements at the end of an existing list. It can append one element at a time.

a = [1, 2, 3, 4, 5]
print(a)

a.append(6)
a.append(7)
print(a)

[1, 2, 3, 4, 5]
[1, 2, 3, 4, 5, 6, 7]

Adding Multiple Elements

list extend() method is used to append multiple items to a list at once. It takes an iterable such as another list, tuple, or a set.

a = [1, 2, 3, 4, 5]
print(a)

a.extend([100, 200, 300])
print(a)

[1, 2, 3, 4, 5]
[1, 2, 3, 4, 5, 100, 200, 300]

Replacing Multiple Elements

To replace or update multiple elements in a list at once, list slicing method is used.

a = [1, 2, 3, 4, 5]
print(a)

a[1:4] = [100, 200, 300]
print(a)

[1, 2, 3, 4, 5]
[1, 100, 200, 300, 5]

Inserting Element

The list insert() method is used to insert an element at a particular index. It takes two parameters, the first is the index number and the second parameter is the value to be inserted.

a = [1, 2, 3, 4, 5]
print(a)

a.insert(3, 400)
print(a)

[1, 2, 3, 4, 5]
[1, 2, 3, 400, 4, 5]

Deleting an Element

There are two ways to remove an element from a list. The list remove() method removes the particular element from the list. It removes the element which is given to it as parameter. Another way is by using the list pop() method, which removed the last element of the list.

a = [1, 2, 3, 4, 5]
print(a)

a.remove(1)
print(a)

a.pop()
print(a)

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