如何卸载lxml以便安装Scrapy？ pip unintall lxml将无效，如下面的代码所示。
在寻找解析XML的最佳方法之后，我偶然发现了Scrapy。我是编程新手，因此Scrapy文档使这个过程变得更加容易。为了使用它，似乎lxml需要去。任何帮助将非常感激。
Parthenon:~ Owner$ pip uninstall lxml
Cannot uninstall requirement lxml, not installed
Storing debug log for failure in /Users/Owner/Library/Logs/pip.log
Parthenon:~ Owner$ pip install scrapy
Downloading/unpacking scrapy
Downloading Scrapy-0.24.4-py2-none-any.whl (444kB): 444kB downloaded
Requirement already satisfied (use --upgrade to upgrade): pyOpenSSL in
/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python (from scrapy)
Downloading/unpacking six>=1.5.2 (from scrapy)
Downloading six-1.8.0-py2.py3-none-any.whl
Downloading/unpacking queuelib (from scrapy)
Downloading queuelib-1.2.2-py2.py3-none-any.whl
Downloading/unpacking lxml (from scrapy)
pip can't proceed with requirement 'lxml (from scrapy)' due to a pre-existing build
directory.
location: /private/var/folders/z_/00h47x3s6ql28yw7tm_l5ts80000gn/T/pip_build_Owner/lxml
This is likely due to a previous installation that failed.
pip is being responsible and not assuming it can delete this.
Please delete it and try again.
Storing debug log for failure in /Users/Owner/Library/Logs/pip.log
Parthenon:~ Owner$