ReactCHALLENGES

15. Comprehension with if

A list comprehension can keep only the elements that satisfy a condition by adding if at the end:

  • condition — a boolean expression that uses item.
  • When it is True, expression is added to the new list; when it is False, the element is skipped.
  • This is a filter: the result has the same or fewer elements, never more.

Coming from JavaScript? Adding if is .filter(): [n for n in numbers if n % 2 == 0] is numbers.filter(n => n % 2 === 0). Map and filter can be combined in one comprehension.

#01

Keep the even numbers

Build a list comprehension with the even numbers of range(6) using if, then print the new list.

Print exactly:

Create a free account to save your progress and unlock chapter 2.

#02

Keep the long words

Use words = ["sun", "python", "code", "hi"]. Build a list comprehension that keeps only the words with more than 3 characters, then print the new list.

Print exactly:

Create a free account to save your progress and unlock chapter 2.

#03

Square the odd numbers

Build a list comprehension with the square of each odd number in range(6), then print the new list.

Print exactly:

Create a free account to save your progress and unlock chapter 2.

#04

Filter and transform

Build a list comprehension that multiplies by 10 each number of range(5) greater than 2, then print the new list.

Print exactly:

Create a free account to save your progress and unlock chapter 2.