Source: 📖 Effective Python item 28

Comprehensions support multiple if statements

You can use multiple if conditions within comprehensions for filtering results. When doing so, these if statements have an implicit and expression between them.

original = [1, 2, 3, 4, 5, 6, 7, 8, 9]
b = [x for x in original if x > 4 if x % 2 == 0]		# equivalent
c = [x for x in original if x > 4 and if x % 2 == 0]	# equivalent

In the example above, the original list is filtered out with comprehensions into b and c to include only elements that are greater than 4 and even numbers. It makes no difference whether or not the explicit and is included in the expression.

See also:

• Multiple looping in comprehensions
• Comprehensions can affect and filter items in a list more clearly than map and filter