List comprehensions are a way to create lists in a very concise way.

Suppose you have a list:

numbers = [1, 2, 3, 4, 5]

You can create a new list using a list comprehension, composed by the numbers list elements, power 2:

numbers_power_2 = [n**2 for n in numbers]
# [1, 4, 9, 16, 25]

List comprehensions are a syntax that’s sometimes preferred over loops, as it’s more readable when the operation can be written on a single line:

numbers_power_2 = []
for n in numbers:
    numbers_power_2.append(n**2)

and over map():

numbers_power_2 = list(map(lambda n : n**2, numbers))