python2.7安装opencv-python（cv2）出错

原因应该是python2.7不再支持安装opencv-python！

 ERROR: Command errored out with exit status 1:
   command: /home/dy/anaconda3/envs/test/bin/python /home/dy/anaconda3/envs/test/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /tmp/tmpqG5FBs
       cwd: /tmp/pip-install-wLT0gB/opencv-python
  Complete output (22 lines):
  Traceback (most recent call last):
    File "/home/dy/anaconda3/envs/test/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 257, in <module>
      main()
    File "/home/dy/anaconda3/envs/test/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 240, in main
      json_out['return_val'] = hook(**hook_input['kwargs'])
    File "/home/dy/anaconda3/envs/test/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 91, in get_requires_for_build_wheel
      return hook(config_settings)
    File "/tmp/pip-build-env-YnYkFW/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 146, in get_requires_for_build_wheel
      return self._get_build_requires(config_settings, requirements=['wheel'])
    File "/tmp/pip-build-env-YnYkFW/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 127, in _get_build_requires
      self.run_setup()
    File "/tmp/pip-build-env-YnYkFW/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 243, in run_setup
      self).run_setup(setup_script=setup_script)
    File "/tmp/pip-build-env-YnYkFW/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 142, in run_setup
      exec(compile(code, __file__, 'exec'), locals())
    File "setup.py", line 448, in <module>
      main()
    File "setup.py", line 99, in main
      % {"ext": re.escape(sysconfig.get_config_var("EXT_SUFFIX"))}
    File "/home/dy/anaconda3/envs/test/lib/python2.7/re.py", line 210, in escape
      s = list(pattern)
  TypeError: 'NoneType' object is not iterable
  ----------------------------------------
ERROR: Command errored out with exit status 1: /home/dy/anaconda3/envs/test/bin/python /home/dy/anaconda3/envs/test/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /tmp/tmpqG5FBs Check the logs for full command output.

解决办法：手动下载安装
1、下载对应.whl文件，cpxx指的是python版本
      下载地址
2、安装.whl文件

pip install opencv_python-3.1.0.0-cp27-cp27mu-manylinux1_x86_64.whl