# Lists

## Lists in Python

```python
my_list = [1,2,3,4,5]
print(type(my_list))
# prints list
```

#### What you can do with lists:

1. You can `pop` out the last element of the list (by default) - (pop method)

```python
my_list.pop()
# This is a mutable object
# Since it is a mutable object you don't have to reassign it to itself
# i.e my_list = my_list.pop()
# It will print the list: [1,2,3,4]

# To pop out the first value:
my_list.pop(0)

# If you capture the retured value
sentence = my_list.pop()
print(my_list)  # This will still be the appended list
print(sentence) # But the poped item is stored in this variable
```

2\. Changing a value in the list:

```python
my_list[0] = 'S'
# Prints ['S',2,3,4,5]
```

3\. List can contain a list:

```python
my_list[0] = ['hello', 'goodbye']
# Prints [['hello', 'goodbye'], 2, 3, 4, 5]
```

4\. Appending lists (append method)

```python
my_list.append('this is a sentence')
# Adds at the end the appended stuff
# Prints: [1,2,3,4,5,'this is a sentence']

my_list.append([10, 20, 30]) # This will not append each number, it will append the list
# It will print: [1,2,3,4,5,[10,20,30]]
```

5\. Sorting through lists (sort method)

```python
my_list = [1,3,2,5,4]
my_list.sort() # It prints [1,2,3,4,5]
# Does not return anything, it modifies the list itself
```

6\. Reverse through lists (reverse method)

```python
my_list.sort()    # Sorts the list to [1,2,3,4,5]
my_list.reverse() # Reverses it to [5,4,3,2,1]
```

`These don't have to be integer, python is smart enough to sort strings as well`

7\. Slicing Lists

```python
my_list = [1,2,3,4,5]
print(my_list[2:]) # prints [3,4,5]
```

`First value in slicing is inclusive, last value is non-inclusive`

8\. The `len` function

```python
item_cound = len(my_list) # prints 5
```

8\. Merging lists together

```python
my_list = [1,2,3,4,5]
another_list [6,7,8,9]
print(my_list + another_list) # This did not modify the lists
# prints [1,2,3,4,5,6,7,8,9]

# To merge:
new_list = my_list + another_list

# To modify one list permanently:
my_list.append(another_list) # Adds the entire list as the last element
```


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