Python 2.7 通过pip安装opencv（虚拟环境）

Question

我正在尝试在虚拟环境 (Python 2.7) 中通过 pip 安装 opencv-python 包。不幸的是，我收到一个错误：

(venv) $ pip2 install opencv-python
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
Collecting opencv-python
  Using cached opencv-python-4.3.0.38.tar.gz (88.0 MB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... error
  ERROR: Command errored out with exit status 1:
   command: /home/pc_user/.venvs/venv/bin/python /home/pc_user/.venvs/venv/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /tmp/tmp7q7z4L
       cwd: /tmp/pip-install-C21PKF/opencv-python
  Complete output (22 lines):
  Traceback (most recent call last):
    File "/home/pc_user/.venvs/venv/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 280, in <module>
      main()
    File "/home/pc_user/.venvs/venv/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 263, in main
      json_out['return_val'] = hook(**hook_input['kwargs'])
    File "/home/pc_user/.venvs/venv/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 114, in get_requires_for_build_wheel
      return hook(config_settings)
    File "/tmp/pip-build-env-2FzygL/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-2FzygL/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 127, in _get_build_requires
      self.run_setup()
    File "/tmp/pip-build-env-2FzygL/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-2FzygL/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 "/usr/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/pc_user/.venvs/venv/bin/python /home/pc_user/.venvs/venv/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /tmp/tmp7q7z4L Check the logs for full command output.

我尝试过创建新环境或通过python2 -m pip install安装，但效果是一样的。有什么问题吗？

Answer 1

Python opencv-python-4.3.0.38 不再支持 2.7。在 4.3.0.36 中放弃了支持；参见 this issue。

我找到的解决方法是安装 opencv-python 版本 4.2.0.32（这是 Python 2.7 支持的最新版本，请参阅 this 了解所有版本），如下所示：

pip2 install opencv-python==4.2.0.32

Python 2.7 通过pip安装opencv（虚拟环境）

Python 2.7 installing opencv via pip (virtual environment)

opencv

pip

virtualenv

python-2.7