Cool New Features in Python 3.5

Transcript

1. Cool new features in Python 3.5

2. None

3. Unpacking >>> a,b,c = [1,2,3] >>> print(a) 1 >>> print(b)

   2 >>> print(c) 3

4. Unpacking: LEVELED >>> a = [1,2,3] >>> b = [4,5,6]

   >>> print([*a, *b]) [1,2,3,4,5,6] PEP 448

5. Build Dictionaries >>> defaults = {"database": "mysql"} >>> my_config =

   {"database": "sqlite", "password": "cats"} PEP 448

6. Build Dictionaries >>> defaults.update(my_config) >>> print defaults {"database": "sqlite", "password":

   "cats"} PEP 448

7. Build Dictionaries >>> print {**defaults, **my_config} {"database": "sqlite", "password": "cats"}

   PEP 448

8. Call Functions with Unpacking >>> connect(**defaults, **my_config) PEP 448

9. math.isclose() >>> a = 1.0 >>> b = 1.00000000001 >>>

   math.isclose(a,b) True >>> math.isclose(1.0, 1.1) False >>> math.isclose(1.0, 1.01, abs_tol=.1) True PEP 485

10. >>> import math >>> math.pow(a, 2) + math.pow(b, 2) ==

    math.pow(c,2)

11. >>> a**2 + b**2 == c**2

12. import numpy as np from numpy.linalg import inv, solve #

    Using dot function: S = np.dot((np.dot(H, beta) - r).T, np.dot(inv(np.dot(np.dot(H, V), H.T)), np.dot(H, beta) - r))

13. @ matrix multiplication operator @ >>> S = (H @

    beta - r).T @ \ inv(H @ V @ H.T) @ (H @ beta - r) PEP 465

14. os.scandir() PEP 471

15. yield from (python 3.4) @asyncio.coroutine def view(request): data = yield

    from db_query(request.q) more = yield from db_query(request.p) return yield from render(data, more) PEP 380

16. async and await async def view(request): data = await db_query(request.q)

    more = await db_query(request.p) return await render(data, more) PEP 492

17. type annotations def hello(name: str) -> str: return "hello, {}".format(name)

    PEP 484

18. type annotations def hello(name: str) -> str: return "hello, {}".format(name)

    def greet(name): print greeting(name) PEP 484 types!

19. gradual typing def hello(name: str) -> str: return "hello, {}".format(name)

    def greet(name): print(greeting(name)) types! no types! PEP 484

20. import typing from typing import List def combine(input: List[str]) ->

    int: return input.join() PEP 484

21. much, much more! PEP 461, 479… • subprocess.run() • collections.OrderedDict

    4-100 times faster • bytes % args, bytearray % args • functools.lru_cache() 10-25x faster • StopIteration handling inside generators better • A new installer for Windows

22. Thanks! https://docs.python.org/3/whatsnew/3.5.html