小编0dm*_*mda的帖子

这是我的代码：

import asyncio
from aiohttp import ClientSession


async def main():
    url = "https://stackoverflow.com/"

    async with ClientSession() as session:
        async with session.get(url) as resp:
            print(resp.status)

asyncio.run(main())

如果我在我的电脑上运行它，一切正常，但如果我在 pythonanywhere 上运行它，我会收到这个错误：

Traceback (most recent call last):
  File "/home/0dminnimda/.local/lib/python3.8/site-packages/aiohttp/connector.py", line 936, in _wrap_create_connection
    return await self._loop.create_connection(*args, **kwargs)  # type: ignore  # noqa
  File "/usr/lib/python3.8/asyncio/base_events.py", line 1017, in create_connection
    raise exceptions[0]
  File "/usr/lib/python3.8/asyncio/base_events.py", line 1002, in create_connection
    sock = await self._connect_sock(
  File "/usr/lib/python3.8/asyncio/base_events.py", line 916, in _connect_sock
    await self.sock_connect(sock, address)
  File "/usr/lib/python3.8/asyncio/selector_events.py", line 485, in …

为什么这段代码不起作用？

def test():   
    e = None
    try:
        raise Exception

    except Exception as e:
        pass

    return e

test()

我收到此错误：

UnboundLocalError：赋值前引用了局部变量“e”

有什么区别？

asyncio.run(func())

和

loop = asyncio.get_event_loop()
loop.run_until_complete(func())

据我了解，区别在于，如果我在已有的程序中使用第一个示例event_loop，则会发生冲突。

如何使pygame.draw.circle透明（添加 alpha 级别），至于“表面”“set_alpha”？我找到了一个解决方案，只是将 的颜色更改pygame.draw.circle为不那么亮

When I run this code:

import cv2

image = cv2.imread('screenshoot10.jpg')
cv2.imshow('input image', image)

gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

edged = cv2.Canny(gray, 30, 200)
cv2.imshow('canny edges', edged)

_, contours = cv2.findContours(edged, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
cv2.imshow('canny edges after contouring', edged)

print(contours)
print('Numbers of contours found=', len(contours))

cv2.drawContours(image, contours, -1, (0, 255, 0), 3)
cv2.imshow('contours', image)
cv2.waitKey(0)
cv2.destroyAllWindows()

I am getting this error:

OpenCV(4.1.1) C:\projects\opencv-python\opencv\modules\imgproc\src\drawing.cpp:2509: error: (-215:Assertion failed) npoints > 0 in function 'cv::drawContours'

What am I doing wrong?

据我从wikipedia了解，git 自 2005 年就已存在，那么我是如何找到某人之前制作的记录的？（这显示在图表上）

github 上的这个提交

gvanrossum committed on 10 Aug 1990 

Run Code Online (Sandbox Code Playgroud)

commit 7f777ed95a19224294949e1b4ce56bbffcb1fe9f