转：pip安装指定版本

 https://blog.csdn.net/youcharming/article/details/51073911

要用 pip 安装指定版本的 Python 包，只需通过 == 操作符 指定

pip install robotframework==2.8.7

将安装robotframework 2.8.7 版本

PS:

python2 的默认mock==3.0.5

转载:ERROR: Cannot uninstall 'PyYAML'. 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

问题:

安装yq时，一直提示
"ERROR: Cannot uninstall 'PyYAML'. 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"

解决:

try using the --ignore-installed flag:

sudo -H pip3 install --ignore-installed PyYAML

This works because to upgrade a package, pip first uninstalls the old version, then installs the new version. It is the uninstall step that fails for distutils packages. With the --ignore-installed flag, the uninstall step is skipped and the new version is simply installed on top of the old one.

https://stackoverflow.com/questions/49911550/how-to-upgrade-disutils-package-pyyaml