Python3.5 筆記.md

##Python 3.5

• ASYNC, AWAIT
• single thread
• event loop
• taskqueue celery == asyncio

Type Hit

• It's just a hint, a comment, let your code be self-documenting.

    def func(x: int, y: int) -> bool:
        return x < y 

• use mypy test.py check types.
• can use another file *.pyi to store the hint.

PEP465 - @ operator

• This still don't be implemented in stdlib, we need to overwrite it by ourselves.
• simplize the expression
• It tooks 7 years to accept this operator.

PEP448

default = {...}
overwrite = {...}
d = {**default, **overwrite}

joint = [*a, *b, *c] # a,b ,c are iterable object.

subprocess

r = sp.run(['ls', '-a']) # CompletePrecess Object.
r.check_returncode()

byteformating

• no .format()
• use str, byte is for low level work.
• .fromhex()

about python on windows

Python3.5 won't support Windows XP

• Embedded version only for Windows(without pip, vs runtime).
• we should ncapesule thard-party librery by ourselves.

PEP428 - pathlib

os.path is old and hard to use.

For example, Path.home() can get the home directory, and also it can be sended to open() to open a file.

BT / BLE / 藍牙

• 藍牙 (O) 藍芽 (X)
• bluetooth SIG is expensive ($ 6000 per device, $8000 a year for membership fee).
• Both WiFi, Bluetooth are using 2.4GHz (ISM band).
• Different from huge band width of Wifi, BT's band width is 2M * 40 channels.
• BlueZ, hciconfig