In some programming languages (especially Python), list comprehension is a method of manipulating lists in a compact/concise way. Comprehensions use the same keywords as loop and conditional blocks, and aim to focus on the actual data rather than on the procedure — which gives us different ways of thinking about our logic.
The general syntax of list comprehension is:
new_list = [expression for item in iterable if condition]Other data types, like sets or dictionaries, also have corresponding comprehensions. That said, past a simple level they stop being useful clarifying tools and we should then just use functions.
Example
To iterate through a list and find even numbers:
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
even_numbers = []
for number in numbers:
if number % 2 == 0:
even_numbers.append(number)With list comprehension:
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
even_numbers = [number for number in numbers if number % 2 == 0]