What's great about comprehensions is that they greatly simplify your code.
Let's show an example. The block of code below is verbose.
old_list = 'abcde' new_list =  for i in range(len(old_list)): if i % 2 == 0: new_list.append(old_list[i]) new_list
It can be turned into a one-liner by using a comprehensions
[char for idx, char in enumerate('abcde') if idx % 2 == 0]