Interesting New Features in Python 3.5 Dr. Brett Cannon Microsoft / snarky.ca Vancouver Python Day, Sep 2015 

Read "What’s New In Python 3.5" for all the details 

async/await PEP 492 

"Coroutines … generalize subroutines for nonpreemptive multitasking, by allowing multiple entry points for suspending and resuming execution at certain locations." 

In the beginning, there were enhanced generators >>> def grep(look_for): ... while True: ... line = (yield) ... if look_for in line: print(line) ... >>> search = grep('Python'); next(search) # Primed >>> search.send('Hi, Ruby?') >>> search.send('Hi, Vancouver Python Day!') Hi, Vancouver Python Day! 

Then came asyncio @asyncio.coroutine def display_date(loop): end_time = loop.time() + 5.0 while True: print(datetime.datetime.now()) if (loop.time() + 1.0) >= end_time: break yield from asyncio.sleep(1) loop = asyncio.get_event_loop() loop.run_until_complete(display_date(loop)); loop.close() 

Now we have async/await async def display_date(loop): end_time = loop.time() + 5.0 while True: print(datetime.datetime.now()) if (loop.time() + 1.0) >= end_time: break await asyncio.sleep(1) loop = asyncio.get_event_loop() loop.run_until_complete(display_date(loop)); loop.close() 

Matrix multiplication PEP 465 

Operator is not implemented by any of Python's builtin types numpy.dot(a, b) a.dot(b) a @ b 

Type hints PEP 484 

Simple example def greeting(name: str) -> str: return 'Hello ' + name 

Take a deep breath & stay calm ● Does not affect runtime semantics ● Meant to act as documentation and help with tooling ○ Just like Dart ● Does not forbid using function annotations for other purposes ○ Does gives them widely recognized default semantics, though ● In no way required to be used ● Doesn't expect everything to be annotated ○ E.g., don't worry about annotating local variables if you don't want to 

Example using the typing module and variable annotations from typing import Mapping, Sequence def notify_by_email(employees: Sequence[Employee], overrides: Mapping[str, str]) -> None: ... x = [] # type: List[Employee] 

Bytes interpolation PEP 461 

Should help with Python 2/3 compatibility b'you can %s bytes' % (b'interpolate') 

Compiler independence on Windows Python is no longer tied to a certain version of VC++ 

Preview of Python 3.6 No rest for the wicked 

Format strings PEP 498 

Prints "I'm in Vancouver learning about Python!" loc = 'Vancouver' lang = 'Python' print(f"I'm in {loc} learning about {lang}!") 

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