# Python List append() vs extend() Method Explained

> Use append() to add a single item to the end of a list, and extend() to merge the items of another iterable onto the end of a list one by one

**URL:** https://sentry.io/answers/append-vs-extend-in-python/

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## The Problem

What is the difference between Python's list methods `append()` and `extend()`?

## The Solution

The `append()` method is used to add an item to the end of a list, whereas the `extend()` method is used to merge a second list (or other iterable) onto the end of a list. Consider the following examples:

```python
# Use of append
products = ["Apples", "Oranges", "Bananas"]
new_product = "Apricots"

products.append(new_product)
print(products)  # will output ['Apples', 'Oranges', 'Bananas', 'Apricots']
```

In the code above, a single item was *appended* to the list.

```python
# Use of extend
products = ["Apples", "Oranges", "Bananas"]
new_products = ["Apricots", "Mangoes"]

products.extend(new_products)
print(products)  # will output ['Apples', 'Oranges', 'Bananas', 'Apricots', 'Mangoes']
```

In the code above, the list was *extended* with a second list.

Now let's see what happens if we swap the methods:

```python
# Incorrect use of extend
products = ["Apples", "Oranges", "Bananas"]
new_product = "Apricots"

products.extend(new_product)
print(products)  # will output ['Apples', 'Oranges', 'Bananas', 'A', 'p', 'r', 'i', 'c', 'o', 't', 's']
```

Here, our use of `extend()` has caused each element (i.e. character) of the `new_product` string to be added to our list individually.

```python
# Incorrect use of append
products = ["Apples", "Oranges", "Bananas"]
new_products = ["Apricots", "Mangoes"]

products.append(new_products)
print(products)  # will output ['Apples', 'Oranges', 'Bananas', ['Apricots', 'Mangoes']]
```

Here, our use of `append()` has caused the `new_products` list to be treated as a single item.

In summary, we should use `append()` when we want to add a single item to the end of a list and `extend()` when we want to merge our list with another.

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*Source: [sentry.io/answers/append-vs-extend-in-python/](https://sentry.io/answers/append-vs-extend-in-python/)*