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Python List append() Method

The append() method adds one item to the end of a Python list.

Use it when you want to grow a list step by step. This method changes the original list directly, so it does not create a new list.

Quick answer #

numbers = [1, 2, 3]
numbers.append(4)
print(numbers)
# [1, 2, 3, 4]

Use append() to add one item to the end of a list. It changes the original list.

What append() does #

  • append() adds one item to the end of a list
  • It changes the existing list in place
  • It does not create a new list
  • It can add any Python object as one item

This means you can append:

  • numbers
  • strings
  • booleans
  • lists
  • dictionaries
  • custom objects

If you need a broader introduction to lists first, see Python lists explained for beginners.

Syntax #

Basic form:

my_list.append(item)
  • my_list is the list you want to change
  • item is the value or object to add
  • The method returns None

Example:

fruits = ["apple", "banana"]
result = fruits.append("orange")

print(fruits)
print(result)

Output:

['apple', 'banana', 'orange']
None

The important detail is that append() updates fruits, but the method itself returns None.

Simple example #

Start with a short list, append one value, then print the list.

colors = ["red", "blue"]
colors.append("green")

print(colors)

Output:

['red', 'blue', 'green']

The new item becomes the last item in the list.

If you want a task-focused guide, see how to add an item to a list in Python.

Appending different data types #

You can append many kinds of values.

items = []

items.append(10)
items.append("hello")
items.append(True)
items.append({"name": "Sam"})
items.append([1, 2, 3])

print(items)

Output:

[10, 'hello', True, {'name': 'Sam'}, [1, 2, 3]]

A list added with append() becomes one single item.

numbers = [1, 2]
numbers.append([3, 4])

print(numbers)

Output:

[1, 2, [3, 4]]

Notice that [3, 4] was added as one nested list item.

This is different from list.extend(), which adds items one by one from another iterable.

append() vs extend() #

This is one of the most common beginner questions.

Using append() #

numbers = [1, 2]
numbers.append([3, 4])

print(numbers)

Output:

[1, 2, [3, 4]]

Using extend() #

numbers = [1, 2]
numbers.extend([3, 4])

print(numbers)

Output:

[1, 2, 3, 4]

The difference:

  • append([3, 4]) adds one item: the whole list
  • extend([3, 4]) adds two separate items
  • Use append() for one item
  • Use extend() for multiple items from another iterable

For the full method reference, see Python list extend() method.

Common beginner mistakes #

Assigning the result of append() #

This is a very common mistake:

items = [1, 2, 3]
items = items.append(4)

print(items)

Output:

None

Why this happens:

  • append() changes the list in place
  • append() returns None
  • So items = items.append(4) replaces your list with None

Correct version:

items = [1, 2, 3]
items.append(4)

print(items)

Output:

[1, 2, 3, 4]

Expecting append() to return the updated list #

Wrong idea:

updated = [1, 2].append(3)
print(updated)

Output:

None

Remember: append() updates the list you already have.

Using append() when extend() is needed #

numbers = [1, 2]
numbers.append([3, 4])

print(numbers)

Output:

[1, 2, [3, 4]]

If you expected [1, 2, 3, 4], use extend() instead.

Forgetting that append() always adds at the end #

append() cannot choose a position. It always adds the new item at the end of the list.

If you need to add an item at a specific index, use list.insert().

Example:

letters = ["a", "c"]
letters.insert(1, "b")

print(letters)

Output:

['a', 'b', 'c']

When to use append() #

append() is useful when you are adding items one at a time.

Common cases:

  • building a list in a loop
  • collecting user input
  • storing results step by step
  • adding one new item to existing data

Example with a loop:

squares = []

for number in range(1, 5):
    squares.append(number * number)

print(squares)

Output:

[1, 4, 9, 16]

FAQ #

Does append() return a new list? #

No. append() changes the original list and returns None.

Can append() add multiple items at once? #

No. It adds one item. To add multiple items from another iterable, use extend().

What happens if I append a list? #

The whole list is added as one item at the end, creating a nested list.

Example:

data = [1, 2]
data.append([3, 4])

print(data)

Output:

[1, 2, [3, 4]]

What is the difference between append() and insert()? #

append() adds at the end. insert() adds at a specific position.

See also #

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