List Comprehensions in Python

• a quick way to create lists

• It consists of brackets containing an expression followed by a for clause, then zero or more for or if clauses. The expressions can be anything, meaning you can put in all kinds of objects in lists.

• Example
• OPTION |

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

• OPTION ||

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

Basic Syntax

square brackets []

More Examples

You can either use loops: squares = []

for x in range(10):
    squares.append(x**2)

print squares
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

# Or you can use list comprehensions to get the same result:
squares = [x**2 for x in range(10)]

print squares
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]