What Is Python?
Python is an Interpreted,
Interactive, Object-Oriented, and high
level programming language and it has design philosophy that emphasizes code
readability.
Python is created by Guido van Rossum and the first
released in 20 February 1991; around 26 years
ago.
Currently, Python 3.8 is in development phase. You can see, much of added and updated features, functionality to the newly released Python 3.7 and 3.8.
1) Coroutines with async and await syntax
Async def syntax -
>>> async def coro():
... return 'spam'
Example -
import asyncio
async def coro(name, lock):
print('Coroutine {}: waiting for lock'.format(name))
async with lock:
print('Coroutine {}: holding the lock'.format(name))
await asyncio.sleep(1)
print('Coroutine {}: releasing the lock'.format(name))
loop = asyncio.get_event_loop()
lock = asyncio.Lock()
coros = asyncio.gather(coro(1, lock), coro(2, lock))
try:
loop.run_until_complete(coros)
finally:
loop.close()
The Output looks like -
Coroutine 2: waiting for lock
Coroutine 2: holding the lock
Coroutine 1: waiting for lock
Coroutine 2: releasing the lock
Coroutine 1: holding the lock
Coroutine 1: releasing the lock
2) A dedicated infix operator for matrix multiplication - a new matrix multiplication operator: a @ b
Previously code looks like -
S = dot((dot(H, beta) - r).T, dot(inv(dot(dot(H, V), H.T)), dot(H, beta) - r))
Now, shorter sweeter and its looks like -
S = (H @ beta - r).T @ inv(H @ V @ H.T) @ (H @ beta - r)
3) Added new library modules - Type Hints
For example, a simple greeting function -
def greeting(name: str) -> str:
return 'Hello ' + name
4) Adding a file system path protocol
5) Formatted string literals
6) Added New bytes.hex (), bytearray.hex () and memoryview.hex () methods
7) Security improvements - SSLv3 is now disabled throughout the standard library. It can still be enabled by instantiating ssl.SSLContext manually.
8) Percept formatting support for bytes and bytearray - adds support for the % interpolation operator to bytes and bytearray.
9) The os.scandir () function is a faster directory iterator.
10) Added Retry system calls failing with EINTR - An errno.EINTR error code are returned whenever a system call that is waiting for I/O is interrupted by a signal. Previously, Python would raise Interrupted Error in such cases. This meant that, when writing a Python application, the developer had two choices-
- Ignore the InterruptedError
- Handle the InterruptedError and attempt to restart the interrupted system call at every call site
11) Added New Modules - secrets, typing and zipapp.
12) Advanced unpacking -
Previously, you can do this
>>> a, b = range(2)
>>> a
0
>>> b
1
Now you can do this -
>>> a, b, *rest = range(10)
>>> a
0
>>> b
1
>>> rest
[2, 3, 4, 5, 6, 7, 8, 9]
13) For 3.8 - Syntax for variable annotations
For example,
primes: List[int] = []
captain: str # Note: no initial value!
class Starship:
stats: Dict[str, int] = {}
14) Underscores in Numeric Literals - adds the ability to use underscores in numeric literals for improved readability.
15) Simpler customization of class creation -
Example,
class PluginBase:
subclasses = []
def __init_subclass__(cls, **kwargs):
super().__init_subclass__(**kwargs)
cls.subclasses.append(cls)
class Plugin1(PluginBase):
pass
class Plugin2(PluginBase):
pass
16) Descriptor Protocol Enhancements
17) Adding a file system path protocol
18) Local Time Disambiguation
19) PYTHONMALLOC environment variable -Newly allocated memory is filled with the byte 0xCB. Now It is possible to install debug hooks on Python memory allocators on Python compiled in release mode using PYTHONMALLOC=debug