【疑难杂症百解_04】pip instal报错：ERROR: Exception: Traceback (most recent call last): File “/Library/.....“

今天在用pip安装opencv-python时，pip install opencv-python后速度极其缓慢，几分钟后提示下载失败，并报错如下：

ERROR: Exception:
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pip/_vendor/urllib3/response.py", line 437, in _error_catcher
    yield
  File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pip/_vendor/urllib3/response.py", line 519, in read
    data = self._fp.read(amt) if not fp_closed else b""
  File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/http/client.py", line 454, in read
    n = self.readinto(b)
    .................................................
	 					
	 					中间略
	 					
	..................................................
  File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/contextlib.py", line 131, in __exit__
    self.gen.throw(type, value, traceback)
  File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pip/_vendor/urllib3/response.py", line 442, in _error_catcher
    raise ReadTimeoutError(self._pool, None, "Read timed out.")
pip._vendor.urllib3.exceptions.ReadTimeoutError: HTTPSConnectionPool(host='files.pythonhosted.org', port=443): Read timed out.

报错原因：

一开始没用弄清楚问题的原因，就盲目搜素了各种办法去解决，比如在命令前边加sudo，但都没有解决，后来找到了根源才知道这个报错是什么意思，感觉自己像个憨憨一样。

⚠️原来这种报错是因为下载外网资源网速太慢了！！

解决办法：

只需切换到国内安装镜像即可，这里我用的是清华的镜像：

pip install opencv-python -i https://pypi.tuna.tsinghua.edu.cn/simple

安装完打开pycharm验证一下，输入代码运行程序：

import cv2
print(cv2.__version__)

不报错并输出opencv版本：

安装成功✌️