python
Python 3.7.1 (default, Dec 13 2018, 22:28:16)
[Clang 10.0.0 (clang-1000.11.45.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
> def a():
...   return 'A'
...
> a()
'A'

ipython

defPython 3.7.1 (default, Dec 13 2018, 22:28:16)
Type 'copyright', 'credits' or 'license' for more information
IPython 7.5.0 -- An enhanced Interactive Python. Type '"htmlcode">

python

Python 3.7.1 (default, Dec 13 2018, 22:28:16)
[Clang 10.0.0 (clang-1000.11.45.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
> import asyncio
> async def b():
...   await asyncio.sleep(1)
...   return 'B'
...
> await b()
 File "<stdin>", line 1
SyntaxError: 'await' outside function


是的，await只能在异步函数里面才可以使用。
Python 3.8的asyncio REPL
好消息是官方REPL也与时俱进，支持asyncio REPL了。具体细节可以看延伸阅读链接1： 


./python.exe -m asyncio
asyncio REPL 3.8.0a4+ (heads/master:8cd5165ba0, May 27 2019, 22:28:15)
[Clang 10.0.0 (clang-1000.11.45.5)] on darwin
Use "await" directly instead of "asyncio.run()".
Type "help", "copyright", "credits" or "license" for more information.
> import asyncio
> async def b():
...   await asyncio.sleep(1)
...   return 'B'
...
> await b()
'B'
> async def c():
...   await asyncio.sleep(1)
...   return 'C'
...
> task = asyncio.create_task(c())
> await task
'C'
> await asyncio.sleep(1)


注意激活REPL不是直接输入python，而是要用 python -m asyncio ，另外那个 import asyncio 是激活REPL时自动帮你输入的。
延伸阅读
先别看代码，看看你能不能实现这个功能 :yum:
https://github.com/python/cpython/pull/13472
总结
以上所述是小编给大家介绍的Python 3.8新特征之asyncio REPL,希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！

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