class08.md

List Comprehensions in Python

• List comprehensions provide a concise way to create lists.

• The list comprehension always returns a result list.

Without List comprehension

new_list = []
for i in old_list:
    if filter(i):
        new_list.append(expressions(i))

With List comprehension

new_list = [expression(i) for i in old_list if filter(i)]

Syntax :

[ expression for item in list if conditional ]

using If with list comprehension

• Genearal Formula:

result = [transform iteration filter ]

• example :

new_range = [i * i for i in range(5) if i % 2 == 0]