List comprehensions are a convenient way to construct lists in Python, using other collections and if statements to construct lists in a concise way. Note that while list comprehensions are not strictly neccessary, they are useful for building lists using clearer syntax, with fewer lines of code. In this sense, they can act as a useful tool for refactoring.

List comprehensions are structured as follows:

$[$expression for item in iterable$]$

You can also include an if statement in list comprehensions. This will act as a filtering mechanism.

$[$expression for item in iterable if condition$]$