Annotations

# Numbers
int_num: int = 68
float_num: float = 32.2
double_num: double = 320.233
 
# String
name: str = "Peter"
by: bytes = b"test"
is_ok: bool = False

# List
num_list: list = []
num_list_specific: list[int] = [1,2,3] ## Python 3.9
 
# Special
mytuple: tuple = ("apple", "banana", "cherry")
mytuple_specific: tuple[int, str, str] = (1, "banana", "cherry") # Python 3.9+
 
mySet: set[int] = {6, 7} ## Python 3.9
myDict: dict[str, int] = { "age" : 30 }
 
whatever: Any = False

from typing import List, Set, Dict, Tuple

def add(a: int, b: int) -> int:
    return a + b
 
def addVoid(a: int, b: int) -> None:
    print( a + b )
 
from typing import Iterator # Python < 3.10+ in case
 
def gen(n: int) -> Iterator[int]:
    i = 0
    while i < n:
        yield i
        i += 1

from typing import Literal
 
def isBigger(a: int, b: int) -> Literal["yes", "no"]:
    return "yes" if a > b else "no"

from typing import Literal, get_args
 
major_types = Literal["CS" , "Math" , "Phy"]
major_list = [m for m in get_args(major_types)] # ["CS" , "Math" , "Phy"]

# Define a type
type Point = tuple[float, float]
 
myPoint: Point = (1.1, 4.7)
 
def makePoint(a: float, b: float) -> Point:
    return (a, b)

from typing import TypedDict
import random
 
class StudentData(TypedDict):
    student_id: int
    major: major_types
    gender: Literal["Male", "Female"]
    gpa: float
 
std: StudentData = {
    "student_id": 0,
    "major": "CS",
    "gender": "Male", "Female",
    "gpa": 3.1
}   
 
std_ls: list[StudentData] = [
    {
        "student_id": i + 1,
        "major": random.choice(major_list),
        "gender": random.choice(["Male", "Female"]),
        "gpa": random.uniform(0, 4)
    } for i in range(10)
]   

from typing import Callable
 
def process_data(data: list[int], operation: Callable[[int], int]) -> list[int]:
    return [operation(item) for item in data]
 
def double(x: int) -> int:
    return x * 2
 
doubled_numbers = process_data(
    [1, 2, 3, 4],
    double
)

from typing import Union 
 
# Python 3.10+
mix_list: list[str | bool] = ["omg", True, "ok"] 
 
mix_list_union: list[Union[str | bool]] = ["gg", True, "ok"]

from typing import Optional 
 
def isBigger(a: Optional[str] = None) -> None:
    print(a)
 
# Other usage beside Optional
def isBigger(a:  str | None = None) -> None:
    print(a)