Like list comprehensions, but for dictionaries: python squares = {x: x*x for x in range(5)} # {0: 0, 1: 1, 2: 4, 3: 9, 4: 16} The syntax is {key: value for item in iterable}.
Another example, swapping keys and values: python original = {"a": 1, "b": 2} swapped = {v: k for k, v in original.items()} # {1: "a", 2: "b"} Comprehensions are concise. Use them when the logic is simple.