Container Hints

So far the type hints have described a single value. Containers need one more piece of information: what's inside them.

list[...]

TypeScript:

let users: string[] = ['John', 'David'];
// or: Array<string>

Python:

users: list[str] = ["John", "David"]

list[str] reads as "a list, of strings" — the type inside the brackets describes every item in the list.

dict[...]

TypeScript's closest match is Record<KeyType, ValueType>:

const users: Record<number, string> = {
  1: 'John',
  2: 'David',
};

Python:

users: dict[int, str] = {1: "John", 2: "David"}

The general shape is dict[KeyType, ValueType] — key type first, value type second, in that order.

list[ItemType]
dict[KeyType, ValueType]

Keep this reading habit — it's the same pattern you'll use to build up the nested types on the next page.