pip install opencv-python报错及相应解决办法

一、安装错误——pip install opencv-python报错

错误描述： 

Please check the install target is valid and see CMake's output for more information.
  ----------------------------------------
  ERROR: Failed building wheel for opencv-python
Failed to build opencv-python
ERROR: Could not build wheels for opencv-python, which is required to install pyproject.toml-based projects  

原因分析：

        原因是使用pip install opencv-python命令安装的是最新版本，python3.6不支持。所以找一个python3.6支持的版本。如opencv-python==4.3.0.38。

解决方案

pip install -i https://pypi.douban.com/simple/ pip install opencv-python==4.3.0.38

二、缺失包——python使用国内镜像安装包

首先下载外网文件速度很慢，这里给出国内源地址

国内源地址：
清华：https://pypi.tuna.tsinghua.edu.cn/simple

阿里云：https://mirrors.aliyun.com/pypi/simple/

中国科技大学 https://pypi.mirrors.ustc.edu.cn/simple/

华中理工大学：http://pypi.hustunique.com/

山东理工大学：http://pypi.sdutlinux.org/ 

豆瓣：http://pypi.douban.com/simple/

新版ubuntu要求使用https源，要注意。

解决方法：

1. # win+R打开cmd命令，切换安装文件夹。

2. # 一般用法

3. pip3 install requests

4. # 加-i用法

5. pip install opencv-python==4.5.5.62 -i https://pypi.tuna.tsinghua.edu.cn/simple requests

三、其余问题（后续有补充在评论区）

错误：ERROR: Cannot uninstall 'imageio'. It is a distutils installed project and thus we cannot         accurately determine which files belong to it which would lead to only a partial uninstall.
处理方法：在pip安装时，不直接采用pip install imageio，而用pip install --ignore-installed imageio就完美地解决了！用这个语句安装之后，pip list后发现还没有moviepy。再pip install moveiepy一下就好了。
参考：https://blog.csdn.net/CSUWoOd/article/details/92066331

错误：Could not find a version that satisfies the requirement cv2 (from versions: )
处理方法：然后我就去安装opencv-python包，打开终端：键盘上的窗口键+R，直接在目录后面输入：pip install opencv-python,等待安装完成即可。
参考：https://blog.csdn.net/lq18804095672/article/details/105096231

错误：WARNING: You are using pip version 19.1.1, however version 20.0.2 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.
解决方法：在命令操作窗口输入python -m pip install --upgrade pip
参考：https://zhuanlan.zhihu.com/p/127062086