In addition to sequence operations and list methods, Python includes a more advanced operation called a list comprehension.

List comprehensions allow us to build out lists using a different notation. You can think of it as essentially a one line for loop built inside of brackets. For a simple example:

In [1]:

```
# Grab every letter in string
lst = [x for x in 'word']
```

In [2]:

```
# Check
lst
```

Out[2]:

This is the basic idea of a list comprehension. If you're familiar with mathematical notation this format should feel familiar for example: x^2 : x in { 0,1,2...10}

Lets see a few more example of list comprehensions in Python:

In [1]:

```
# Square numbers in range and turn into list
lst = [x**2 for x in range(0,11)]
```

In [2]:

```
lst
```

Out[2]:

Lets see how to add in if statements:

In [5]:

```
# Check for even numbers in a range
lst = [x for x in range(11) if x % 2 == 0]
```

In [6]:

```
lst
```

Out[6]:

Can also do more complicated arithmetic:

In [7]:

```
# Convert Celsius to Fahrenheit
celsius = [0,10,20.1,34.5]
fahrenheit = [ ((float(9)/5)*temp + 32) for temp in Celsius ]
fahrenheit
```

Out[7]:

We can also perform nested list comprehensions, for example:

In [8]:

```
lst = [ x**2 for x in [x**2 for x in range(11)]]
lst
```

Out[8]:

Later on in the course we will learn about generator comprehensions. After this lecture you should feel comfortable reading and writing basic list comprehensions.