# Sequence Types: list
{:.no_toc}

<nav markdown="1" class="toc-class">
* TOC
{:toc}
</nav>

## The goal

> Lists are **mutable** sequences, **typically** used to store collections of **homogeneous** items (where the precise degree of similarity will vary by application).​

[Quote](https://docs.python.org/3/library/stdtypes.html#lists)

Questions to [David Rotermund](mailto:davrot@uni-bremen.de)

## Example Lists

With homogeneous items:

```python
primes = [2, 3, 5, 7]

collection_of_strings = [
    "AA",
    "BB",
    "CC",
    "DD",
    "EE",
    "FF",
    "GG",
    "HH",
]
```

A mixture of type:

```python
def my_function(a):
    return a

my_favourite_things = [32, "sleep", my_function]
```

## Indexing

```python
collection_of_strings = [
    "AA",
    "BB",
    "CC",
    "DD",
    "EE",
    "FF",
    "GG",
    "HH",
]


print(collection_of_strings[0])  # -> AA
print(collection_of_strings[1])  # -> BB
print(collection_of_strings[-2])  # -> GG
print(collection_of_strings[-1])  # -> HH
```

## Slicing

```python
collection_of_strings = [
    "AA",
    "BB",
    "CC",
    "DD",
    "EE",
    "FF",
    "GG",
    "HH",
]


print(collection_of_strings[0:3])  # -> ['AA', 'BB', 'CC']
print(collection_of_strings[:3])  # -> ['AA', 'BB', 'CC']
print(collection_of_strings[3:])  # -> ['DD', 'EE', 'FF', 'GG', 'HH']
print(collection_of_strings[1:-1])  # -> ['BB', 'CC', 'DD', 'EE', 'FF', 'GG']
print(collection_of_strings[-3:])  # -> ['FF', 'GG', 'HH']
```

## Changing lists

```python
collection_of_strings = [
    "AA",
    "BB",
    "CC",
    "DD",
    "EE",
    "FF",
    "GG",
    "HH",
]

collection_of_strings[3] = "II"
print(collection_of_strings)  # -> ['AA', 'BB', 'CC', 'II', 'EE', 'FF', 'GG', 'HH']
collection_of_strings[:3] = ["JJ", "KK", "LL"]
print(collection_of_strings)  # -> ['JJ', 'KK', 'LL', 'II', 'EE', 'FF', 'GG', 'HH']
collection_of_strings[:4] = [
    "MM",
    "NN",
    "OO",
    "PP",
]
print(collection_of_strings)  # -> ['MM', 'NN', 'OO', 'PP', 'EE', 'FF', 'GG', 'HH']
```

## List functions

### [len()](https://docs.python.org/3/library/functions.html#len) and [sorted()](https://docs.python.org/3/library/functions.html#sorted)


```python
collection_of_strings = [
    "GG",
    "HH",
    "AA",
    "BB",
    "EE",
    "FF",
    "CC",
    "DD",
]


print(len(collection_of_strings))  # -> 8
print(sorted(collection_of_strings)) # -> ['AA', 'BB', 'CC', 'DD', 'EE', 'FF', 'GG', 'HH']
```

### [max()](https://docs.python.org/3/library/functions.html#max) and [sum()](https://docs.python.org/3/library/functions.html#sum)

```python
primes = [2, 3, 5, 7]
print(sum(primes)) # -> 17
print(max(primes)) # -> 7
```

### [append()](), [pop()](), and [remove()]()

```python
collection_of_strings = [
    "AA",
    "BB",
    "BB",
    "CC",
    "DD",
    "EE",
    "FF",
    "GG",
    "HH",
]

collection_of_strings.append("II")
print(
    collection_of_strings
)  # -> ['AA', 'BB', 'BB', 'CC', 'DD', 'EE', 'FF', 'GG', 'HH', 'II']
print(collection_of_strings.pop())  # -> II
print(
    collection_of_strings
)  # -> ['AA', 'BB', 'BB', 'CC', 'DD', 'EE', 'FF', 'GG', 'HH']
collection_of_strings.remove("BB")
print(collection_of_strings)  # -> ['AA', 'BB', 'CC', 'DD', 'EE', 'FF', 'GG', 'HH']
```